Yes, why, how come these are running under Wine when there are the Mac native originals ??

I can only assume it is so that they run on later OS that has no Rosetta ?

EDIT: OK, sorry I realise now there no Intel native versions of 1,2 and 3 :)

According to Spiderweb Software, Avernum 1 to 3 don't currently run on OS X 10.7 or later (like you, I'd guess that they are PPC programs).