Probably was just for the old Intel Macs.

Proton/Wine could be used on OSX for a long time. Wine for ARM has also been a thing for a while. But it only worked with ARM Windows software.

Combining Wine with x86 emulation has also become a thing in the last few years. And rumor has it that Valve have beem dabbling in it as well for Deckard. But I don't think it's very widespread yet.

But that is probably about to change when Valve are increasing their ARM Mac efforts.