Retro Games Corps got hit, even though Russ only does legal emulation and backups. It’s his “2nd strike” on YouTube (3rd is channel deletion). He’s always been mindful of the situation and considerate of not spoiling games or encouraging anything close to piracy from what I’ve seen.
Source: Nerd Nest where he often guests.
Yep, basically that. No you don’t need it to launch games, I would skip it if this is your only game from GOG.
I don’t game on Mac these days but that seems very plausible.
If you do want another launcher option, Heroic works on Mac. I’m not sure if it gives any different options on what version to install. https://heroicgameslauncher.com/