I guess it depends on what you mean by 'use.'
My Traveller games aren't very combat heavy at all, but every PC gets a miniature (painted by me) to be used when actual position is very important. But that's not very often (Fate doesn't get that granular). The mini generally is used as a 3d character portrait. I certainly don't use them to turn an RPG game into a miniature wargame.
Given that, I do have an extensive collection of 28mm/15mm/mm figures and terrain to match (boxes of terrain for Infinity, Stargrunt, Battletech, etc) as well as spaceships and sometime I do run miniature wargames set in the Traveller universe.
So, yes, but no. But yes also.