It seems like a good idea to me. Having to pay a mortgage is just another cash outflow that inhibits one's ability to take risks.
Sure, you can increase your net worth faster if you don't pay down the mortgage early. Everyone around here knows that. But if you're determined to take control of your life sooner rather than later, not be a slave to the man, and start using more of your time the way YOU want to use it, doesn't it make sense to go ahead and eliminate your biggest monthly expense ASAP?
To somebody who knows he or she will be working in a salaried position until retirement, early mortgage payoff isn't as practical. You're going to put in 40 hours per week until you hit your FIRE date, mortgage or no.
But for a self-employed person, the calculus is different. If I lay waste to my mortgage, I can suddenly free up all the hours I was working to pay for it. For me, maybe that's 3 days per month. For you, maybe it's a week.
Whatever the case, the entrepreneur can use that extra time to pursue new business ventures, spend more time with the spouse and offspring, or... whatever.