Since only artistic media which interest me are games and books, I applaud this idea.

Also very true. :) I actually listen to podcasts while playing parts in video games I already know, like doing another run in Dead Cells. But if I listened to I Have No Mouth And I Must Scream for the first time, I might not want to do anything else simultaneously - not even playing the game of the same name and certainly nothing cheerful.

As for text-to-speech, I personally feel like the technology is still a long way away from resulting in an enjoyable reading experience, although it got better during the last decades.

This would definetely be an interesting idea, if implemented correctly. Would be interested to see where this goes! :)

Actually, if they were video game themed or inspired ebooks, I'd support this. Would be next to buy The Witcher books from GOG instead of Amazon (I already bought almost all of them, just saying) Or books like Dragon Age or Mass Effect.

Good luck with that. I've bought quite a few GOG games that don't even come with the manuals, so I doubt they'd be able to offer up much that isn't already available free elsewhere.

While I realize that it is meant as a form of protection against piracy, I don't personally view watermarks as DRM as it only hinders copyright-infringing use of the product and doesn't affect the legitimate use cases (ie, backups, offline usage, ability to function on any device) that I have in mind.

Technically, they do often sell those in deluxe expansions and DLCs containing game extras (not guides, but game-related novella, comics and the like).

And yeah, you are right, this is one very specific niche of ebooks that actually suits GOG very well.