It's still a damn good deal. They've run out of keys for a lot of games due to the popularity of it. The Witness and Stardew Valley are worth the price alone IMO
So it's debatable because you own the games already! If someone doesn't own these games it's an amazing deal (or if they want to buy keys for their friends and support the devs/charities.)
The Witness can be had for $20 these days, and is definitely a title worth buying if you're into the art-side of gaming. If you're looking for something non-casual and full of inflated statistics and unlocks then go that route and buy those games instead! (and the inevitable DLC that comes with them.)
I play CS:GO competitively on various ladders and completely approve of a lot of these "casual" titles. To dismiss it because you already own some of the games makes sense to you but not to others who don't own them already.
What games? I took a glance at the list again and nothing really jumps out at me
I don't own any of those games, nor have I heard of any of them. Looks like a bunch of shit indie titles that are given away for free every month for PS Plus subscribers.