Achievements could be a nice addition for some people, but are arguably, in fact, not drm-free friendly at all. As in being a feature linked to a store. And that makes it a drm feature by definition.
^ I agree with this. The best way of adding achievements is for the developer to do so natively within the game (eg, Dragon Age Origins) where they get written once and then work equally on every store they're sold on (and even work on offline retail discs without any client at all). But Steam, Galaxy, etc, client level achievements end up locked to stores which increases developer workload by having to be re-written for each future client after the first one (which doubles down on 'Steam first and anything else is more hassle'
Store-front locked features have never really been a positive thing for releasing on multiple stores, first with Steam using them to discourage releasing on secondary platforms, then with Galaxy putting devs in a "choice of two negatives" position where they either deal with complaints for lack of achievements / cloud saves, etc, on GOG or end up putting in more effort to release on modern GOG + Galaxy integration than they did pre-Galaxy when the same single "clean" build could just be uploaded to GOG, Humble, itch.io, etc, simultaneously with no store-front specific integration work required (which is what one big incentive of doing a DRM-Free release should have been heavily advertised to devs all along).
I'm not going to bash anyone for liking achievements, but if a dev feels it's both "expected" to have full Galaxy integration yet at the same time isn't willing to do the client re-intergration work per store, then it may mean the difference between seeing a 'basic' GOG version vs not at all, at which point "Wanting achievements on GOG should have no impact on DRM-Free"
isn't quite as clear cut as some would like to believe.