I don't think you'll get many here who don't see FFB as a bare-minimum requirement for sim racing. Whatever works for folks works for 'em, though, it's their life. One could argue many arcade-oriented titles are made overcomplicated by FFB, ones designed for controller use.
But for sims, it's a crucial piece of feedback that would feel a lot like being blindfolded to go without. It's more than just gimmicky immersion -- it's a sensory connection to the simulator as vital, in my opinion, as seeing or hearing it. You could theoretically go without... but if you had the option, why would you??
Learning to read and respond to FFB was how I managed to build up the confidence to turn off most of the assists on the sims I play.
Except for auto-clutch... but we'll get there one day, I'm sure.