If you’ve got a good, big cloak and it starts drizzling at Picnic Day, you and three small children can sit on a hay bale with all three of you sheltering under the cloak.
Superman’s cape doesn’t go all the way to the floor. It stops about a foot or so short of that. Batman’s cape, on the other hand, not only goes to the floor, but should drag several feet along it. At least that’s the length it’s usually drawn but comics are inconsistant and sometimes it’s drawn shorter than others.
What keeps it from falling back?
ETA: It occurs to me, you could build shoulder straps into a cape so it’s worn like a backpack. I’ve never seen one like that before. I wonder if that’s feasible…
Dang, no wonder I lost my last duel!
Dan
I don’t really think there’s anything a cloak offers that can’t be done better by a long coat. If it’s windy, you can button it up and stay warm. If you want that effect where it trails behind you as you run dramatically it will do that if you leave it unbuttoned. A cloak is an unfinished coat.
I think that’s the main reason you rarely see cloaks worn anymore.
In theory you can wear a coat like a cloak, and I recall some old-fashioned styles where you would take a sleeved coat, wear it on your shoulders (arms not through the sleeves), and have some kind of chain across the front keeping it from falling off. I believe that gentlemen would wear a doublet that way in Renaissance Italy.
Well nowadays coats are cheap, well made, mass manufactured, for any size, and with a speedy supply chain for custom orders. The practicalities of it’s design are no longer offset by it’s price/labour. It simply has the solid edge over cloaks nowadays (outside of aesthetics/tastes).
Ayn Rand often wore a cape.
And back in the '60s, I owned a few ponchos.
You’re a terrible salesperson. 
Somewhere there’s a “rainbow bridge” where we’ll be reunited with the clothes we loved and lost, and my cloak will be there.
I had it when I was an older teen. I felt confident wearing it, as if I was making a fashion statement, and it was practical too. It was well-cut and draped nicely, sat on the shoulders comfortably and didn’t fall off, and it had an easy neck fastener. It was calf-length, chocolate brown, looked great over anything-- a blazer and skirt with boots, jeans. It kept rain off; with it and a big hat I didn’t need an umbrella.
Then we moved to a tropical climate for several years and goodbye forever 
. Since I moved to the Northeast US 30+ years ago I’ve looked in vain for a similar cloak.
What purpose does a Superman style cape serve?
ETA: Was it a Kryptonian fashion statement? Did Jor-El wear one?
What about a Batman style cape? If it dragged on the floor, isn’t that just a tripping hazard?
Mostly the weight of the part that sits in front - capes don’t just run down your back, they sit over your shoulders and drape across onto your chest. And also any ties or clasps., but the ties should be across the top of your chest, not around your neck.
I have to ask - have you ever worn a cloak for an appreciable length of time?
In any case, if it’s super-windy, you can throw one side over the other shoulder, poncho-style. I’ve done this in gale-force winds and stayed toasty.
Not mine, they’re completely different cuts.
They make better blankets. But yeah, as a garment, a long coat is better in these modern times.
The vast majority of the weight is in the back. The weight on your shoulders isn’t going to keep it from slipping off. Not when you move the cape off if your arms. We’re not talking about a poncho here.
The ties are across your chest sometimes. But a cape will shift as you move, and it will occasionally move uncomfortably against your neck.
It’s absolutely possible to rig some kind of harness to attach a cape to (not unlike my backpack idea) but that’s not how capes are made.
More or less. Of course, there’s something like 80 years of altered continuity, retcons, and weirdness in the Superman franchise, but the usual explanation is that it, along with a headband (which Supes doesn’t wear) were normal male attire on Krypton.
Fear and intimidation.
I saw the version of Hamlet with Mel Gibson in the theater. At some point one of the characters throws his cloak over his shoulder and fastens it with a cloak pin. I actually out loud said for some odd reason, “so that’s how a cloak pin works”.
My friend who got her degree in costuming said " yes" in an annoyed voice
Isn’t a large parka much more practical?
You can use one as a cloak if you want to, but you can also use the sleeves and close the zipper and be really warm and also be able to move. (Move as in “go snowboarding” not “walk slowly from your car to the shops”)
Nurses in UK and Australia wear capes when not actually attending a patient. The rule is that one may not wear long sleeves for hygienic reasons but a hip length cape can be flicked back over the shoulders, leaving the arms free to work and the cape stays on.
It is more of a symbolic tradition these days but older nurses guard the insignia on their capes.
Sure, but roughly 90% of the time, the cape is shown in an action panel and it’s more or less flying through the air. Sometimes he even uses it as a hang glider wing to slow and direct a fall.
Capes seem to be a DC superhero thing. I’m not up on all the superheroes out there, but I can’t think of any Marvel ones that have a cape. Dr Doom has one, but he’s a villain. And even many DC superheroes don’t wear one. Supes, Batman, Robin, Supergirl all do, of course. The original Green Lantern did, but later ones didn’t. Don’t seem to be a whole lot of others.