There are reasons why to use flux core and reasons why to use mig/gas welding.

Flux core is excellent for windy conditions. It is good for dirty metal. It is good for portability as you need no tanks. Flux core has some excellent penetration properties.

Flux core is bad if you want less splatter and clean up. Flux core is bad if you want to do thin sheet metal.

Mig / Gas welding is good for thin sheet metal. Mig welding is good for clean welds. Mig welding is just about on par with flux core as far as costs go. Initially mig costs more but if you do a lot of welding on new metal, then mig is the way to go. Less clean up time and better looking welds.

Any time I weld something with new metal, it is always mig. If I am fixing some old metal or outside in the wind, it is then flux core.

There are uses for flux core and there are uses for mig. I would go with a machine that can do both. That will give you the flexibility you need for any type of welding.