I think that depends on which game you start with tbh. But I wouldn't know. Like, sure, 'mill' is a bit obscure if you don't know card game terminology, I guess, but I'm pretty sure 'sacrifice' is pretty easy to understand pretty quickly, and I feel like it would be weird to expect that there necessarily has to be an upside. I also don't really find the same level of questions be brought up over the terminology when other games use it unless there's some other ambiguity that game has. By that logic, we need to argue that 'destroy' also has rules baggage. Tbh, I also base my viewpoint on the idea that this game seems to have a number of clear mtg references (the industrial pieces in particular), so something more closer to it or hearthstone or something in text makes more sense.
If anything, though, if we're not using 'mill' as a keyword, I 100% would be against using 'discard' in its place. The whole benefit of keeping 'discard' to be from hand to graveyard is it cuts out writing "discard from your hand" (since you literally always discard from your hand)
