Always nice to see Joshua Malina, even if he was just a straight man for a Sheldon bit.
But that was the B plot anyway. This episode belonged to the girls, and they killed it! “We have a problem. I look amazing in ALL these dresses!!” 
That whole episode was one that showed how this show has lasted for years. And the next two promise to be great, what with the “Smamy” wedding.
So how does he pay rent, buy all his comic book stuff, and so forth?
Last week’s was fun. This week’s was even funner. And I got real feels when Sheldon told Amy she looked like a pile of swans. sigh
Caltech employees are apparently mostly paid by direct deposit to their bank accounts. I think we can just ignore the claim that Sheldon leaves his paychecks in the basket. That’s just silly, and it’s one of the claims made at some point on the show that show that sometimes the writers ignore obvious facts:
http://hr.caltech.edu/services/online_resources/direct_deposit
Sheldon had tracked the wheel for hours (five, if memory serves) and spotted a bias (and one of the numbers he called as more likely hit as they carried him out).
And the casinos watch blackjack like a hawk for counters and/or suspected counters. The reason the MIT scheme worked is that some people counted, and others with no obvious connection swooped in to bet when the odds swung the players’ way.
That dress, whatever its other faults, did not have a train. And Sheldon had earlier admitted that the train of a wedding gown was the only kind of train he didn’t like.
Note that it was established that Amy is a big fan of Little House on the Prairie, and the wedding dress looks like one that someone on that show would wear:
I think the checks Sheldon doesn’t cash are birthday checks from Meemaw.