Actually that is not entirely true.
There are assault vehicles which are great (Venom/Raider) but the units transported are lackluster.
Then you have the big assault vehicles with solid troops that crouch across the battlefield in a painful slow pace.
The assault flier is in fact a good compromise.
Yes, you probably only arrive at turn 2. But then you safely assault in turn 3 nearly anywhere on the board without exposing your troops or having a vehicle made of wet papertowels.
Is it worth? Probably not.. its still melee. Is it really THAT bad? Not at all.