They specifically state that they won’t use your data for commercial purposes. Until the company merges or gets bought I guess.
Which you won’t hear about until after all the existing data has been scraped off the servers. The company, if bought, will be bought for the value of their data stores and whatever corporation purchases them will specifically want to keep the news quiet until after they’ve gotten their value out of the data store. Therefore this is a non-starter as you may as well just hand the info to Dropbox today.
I must not, because I see zero difference between Steam and GoG in this regard other than the fact that Steam provides a bunch of side services that GoG does not. Otherwise they’re both just selling you a revokable license to play a game.