Ground/Fighting combination has the following positives
Strong against Rock, and Normal types, Dark
and Poison, and Fire, and Elec
Weak against, Psychic, Ice, Water and Grass
Ground stat makes the Flying type 1X instead of 2x
HOLY SHIT
The offensive coverage is insane
If it uses a Ground type move against Poison it would knock Poisons out
but Fighting won't be much effective so its just a 2X from its Ground type stab bonus
But even still
A Ground/Fighting may be the most stable if not the most heaviest hitter with slow speeds but amazing Attack/Defense all around
Imagine
Its Fighting type would also Trump Steel
Hell
4X
Unless if another Pokemon uses Knock-down or Gravity to make it land
negating its Levitate
But you can bet loads of money that it can knockout a Steelix in one blow
Well maybe two hits tops if it has Sturdy
Ground/Fighting is super OP with the coverage.