Throwing my hat in the ring on this question, I use proxies in mtg as one-part "That's a cool deck, I wanna build that" and one-part art project where I make either sexy arts or experiment with art in general. Like I don't proxy a single card to make a deck better, I do a full deck with new art and enjoy it that way. Currently got a proxy order on the way that's one deck of all redheads (non-lewd, done with the smexy for the moment) and one deck where I wanted to try my hand at actual card design so I made some fun fake cards and also did proxies for the regular cards I wanted to include because that way I don't have to worry about any problems with possibly telling cards apart even when sleeved.

Proxies can be more than just fake cards for powerful decks or cheap versions before you buy the real thing. I don't do mtg comps or anything so who gives a fuck whether this copy of picrel is real? I wanted to do a fun art thing, and I've done it.

And yes, it's AI, I can't draw to save my life, but that's a discussion for a separate thread