i signed over my old iOS game forget-me-not to them, after seeing they're run by some people from touch arcade who i'd had contact with before, and who seemed on the level.. and the fact that it was literally no effort required on my part - i'd long since abandoned making games for phones, and i don't even have any apple hardware any more.. my game was in a semi-unbuildable state.. it was dust. for the last couple years it had still been on the app store, i'd set the price to free anyway..
so yeah i just transferred ownership of it (the app store entry - not the IP or anything else) to them, signed a publishing agreement type thing, sent the source code, received an advance.. no hassles. they updated it and fixed it up..didn't even ask me any questions about the code, or the annoying thing where people ask you for promotional materials!
i doubt i'll get any future royalties from it, my game's probably the most old fashioned and niche type thing on there

but the alternative was...nothingness... so seemed cool to me!
i hate the idea of game subscription things and have no interest in using one at all. BUT, a nice thing about that gameclub is, whoever had previously bought one of the games (in its previous incarnation, before it was delisted and then transferred to gameclub), gets it for free, forever, no subscription even needed. that's really friendly! i very much approve. sooo basically they paid me to update my game for me, and all my old players can just go download it, hehe..
i guess whether it's worth it just depends on if you care about having exact control over your old games..for me, i don't really care at all, just so long as their update runs well and doesn't have ads or iaps or something... fwiw, ymmv etcetc.
(i don't even play phone games nowadays, but hell yeah new fancy versions of some of those mino project games for whatever platform, that'd be rad!)