During the short time I had the 15 Pro the main thing I felt was the balance was off. I can usually juggle the mini with my fingertips, but with the Pro I always felt its instability in my hand. I found I was always needing to use a second hand to get everything recentered. I'm old, but I correct declining vision with readers, so screen size was a minor issue. I could read the mini ae easily as the pro. Where the Pro killed me was the added hand manipulation exacerbated my problem with arthritis. it's amazing a few millimeters can make such a difference. Weight was not an issue.And plenty of us find 6.1 and 6.7 inch phones are also not a great experience.
Any phone which is too big to use one handed to me is not worth a dime.
My 13 Mini is plenty big enough.
Please, no Jitterbug jokes.