yeah pretty much my experience with dual extrusuion.

It's useful to have a flexible filament loaded on one extruder and rigid on the other.
My creator pro clone isn't idex. but it is a decent dual extruder.

I primarily use it as my flexible filament printer, as it's currently the best flexible machine I have.

I can count the number of dual material prints I've done in 6 years on the fingers of one hand (and I'm not a multi fingered genetic abnormal :-)

But it's there in the off chance I ever get round to using the soulble support filament I have.
Given that I've never needed to use supports for any of my designs, the two colour or two material option is what's more likely to be used.

So yeah, single extruder printer is absolutely fine.

Another reason to go with the x-max - fred's got one and will happily answer all your queries ;-)