if you pass on this house, and look at a semi-traditional "colonial" you may find that often the traditional family room which is often situated behind the garage is often built on that same slab/pour.
our mid 90s built home is built that way.
chief gripe about the slab? if we're rough-housing with the kids in there, it hurts more if someone falls/gets slammed into the floor
chief benefit of the slab? it doesn't creak, groan like the wood floor areas of all too many houses built in that era.