Sure, they work. I gave me Grandma my old iMac and she uses it to this day. But it's impossibly slow, as is my 2015 iMac that I'm writing this on.
Restarting this $2500 computer takes several minutes, opening applications takes similar period of time. The computer lags when you open ANY save dialog. Even opening finder takes about 1 second.
Meanwhile I also have a five year old Windows PC I built myself, restarts in under 15 seconds. As soon as I see my desktop I can launch any application instantly.
I like using OSX but it's fucking slow.