Does it make sense to pay tuition fees for a PhD degree?
Nobody will ever know. In fact, nobody will likely ever ask you about this.

At the end of the day, for an academic career, what matters is that you have a PhD and have shown an ability to do independent research. Who paid for the PhD never enters these sorts of considerations: You may have been funded on grants and only done research, or you may have been a teaching assistant to get a salary and have tuition paid, or you may have paid for the tuition yourself. It really doesn't matter, and nobody will care. What people do care about are your qualifications.