I think most mature businesses owners would want a mercenary as opposed to a fanatic. If you're doing it for the money, you'll work as part of the team to execute the leader's vision. If somehow you feel you were made to do this, presumably you also come with a bunch of baggage about how you think the product should be, etc etc which maybe is helpful as a co-founder but could be a hassle as a junior dev.
I’ve been on both sides of that table in my career.
As a business owner today, I definitely want a mercenary. A well prepared and thorough mercenary.
The only business I’m willing to be an “owner” of these days is my own. I’ve worked for my dream employer and “took ownership” and learned a few good lessons about how when you don’t own your dream job, it can (but won’t always) become a nightmare.
Personally I've had great luck with mercenaries.