vulchor: What would be the point of this, when none of the games on GOG support ARM architecture? Considering how long and grueling the development of GOG Galaxy has been just on x86 architecture, I wouldn't hold your breath waiting for support on a completely different architecture.
The point is to support platforms other than just Windows, and provide the tools for developers and publishers to broadcast their games towards more audiences. While Windows has the biggest market share, it wouldn't hurt to update the Mac app. Heck, it wouldn't hurt to make a Linux client to begin with.
There are also a few titles that are Apple Silicon native on GOG, some examples are Tunic, Songs of Conquest, Disco Elysium. They run great when using the native binary, sometimes way too good! Unfortunately, running the native client requires you to run without GOG Galaxy client open. Meaning all the time tracking, achievements, and online play capabilties are affected. Not to mention the overhead that GOG Galaxy creates during translation... its not ideal.
While its true that there aren't many games that support it, providing a client allows for future games to support said architecture and provide additional revenue for those who want to support macOS. Developing for arm isn't easy but also not impossible, specially for medium size entity such as CDProjeckt. It is not an impossible task as some make it out to be, but its not a walk in the park either. I mean, we really have been running a beta client for so long and with the forums section being hidden in the client.
I do understand however that the majority of games are mostly just Windows focused, I still believe that we should encourage to support other platforms. Nobody wins if only one platform is supported, heck its a bad idea to have less choice just because everyone is on Windows and therefore always be on Windows. Also, keep in mind that Apple nor Microsoft are you friends... they both have only the intentions to profit. So we should make it more competitive!
I hope that answered a few of your questions.