Given the site, how many of those 1427 games be absolute garbage?
So many. For that price, I figured it wouldn't hurt, and I've been going through page by page writing a list of the stuff that looks remotely interesting for later download. I did come across Blades in the Dark, but that's something that would really only appeal to someone who'd probably like Powered by the Apocalypse, which I don't think is particularly popular around here. But for anyone who is a fan, a $5 copy of BitD with a bunch of other optional stuff attached to it isn't bad. (I also didn't see anything objectionable about the particular charity, so I had no qualms about participating. I do read up on charities a little before supporting them. I might have missed something, but I tried.)
ETA: If you go into the video games, the value goes up exponentially. You've got Celeste, which is like an award-winning platformer that is highly demanding but also very fair and approachable due to the way it almost entirely eliminates downtime. Night in the Woods is a little indie darling that's basically you going around your old hometown making decisions that affect things visual novel style. A slice of life thing. Pyre is an RPG from the guys behind Bastion and Transistor, so worth a look I'm sure. And Ganbare! Super Strikers is just an unholy combination of jRPG and soccer, which at least sounds interesting. And I'm only a few pages in, so . . . yeah, definitely not a bad value for your $$$.