I've never quite understood why they just can't save their money and go to a pro. I mean anyone with a job is then effectively not incel.
Some do and think it's great (and presumably stop hanging around incel communities). Some would but are worried about the legal consequence.
But mostly, incels don't just want sex. They want the status and validation of someone showing interest in them
for them, they want the companionship that comes from a romantic relationship. They can't get that from a sex worker.
Sex is a cultural symbol of all that, which is why they focus on the 'celibacy' aspect in their self-description, but they will not be happy with sex without all the rest any more than they'd be happy with masturbation.