It’s a good idea to get scratch resistant reading glasses–as reading glasses seem to collect scratches easily.
They correct close-up vision. They do not correct distance vision, and in fact will usually make it worse. Vision is not a one-size-fits-all thing to correct: Your eye needs to focus differently to see distant things clearly than to see nearby things. Most of us, when we’re young, our eyes can change shape slightly to get this change in focus, but as we age, that ability is often diminished or lost, and so we need to use different glasses for near and far vision to compensate.
Regular glasses accommodate a far greater range of issues, including centering of the lens, astigmatism, and differing eye focus issues. There are too many variations to make stocking them all impractical. Regular glasses are custom fit for a reason.
The cheap drugstore glasses are magnifiers to help aging eyes. As your eyes age, they become less able to focus up close. You run into the problem that your arms aren’t long enough - in order for the book/paper to be far enough away to focus on it, you have to get farther away than the length of your arms.
Also, once you get it far enough away, the print is too small to see. The cheapos allow you to focus as if the object is farther than it is. If you have significant difference between both eyes, it may be difficult to get a pair that works with both eyes.
These are the same thing as what they do with bifocals - the bifocal is adding that additional correction in the lower part of the lens where you look to read up close.
I used to use the cheapies from Wally World, but got tired of having to carry them around. So I broke down and got a pair of prescription Ray Bans. Basically clear lenses with a progressive bifocal. Now I can wear them all the time. Since they were about $300 I do get paranoid about losing them.
Costco sells pretty reasonable 3-packs of reading glasses. They don’t look awful and seem to be fairly well made. I think they are less than $20 for 3 pairs.