Battery life is much worse but when you go all in on next gen Mirrorless cameras there are gains that are just impossible otherwise in a DSLR. The thing that convinced me was using an A7RII 5 years ago in NYC at night. The simple fact of the matter was that the camera could focus and validate setup in the dark better than my own eye with my personal Canon DSLR, even with the wide open nifty 50. I think we are on the edge of major innovations in camera tech. The size advantage makes it easier to carry more batteries as well.
Really the biggest thing is that Nikon is just brutally behind in tech compared to Sony and even Canon. The market has moved past DSLRs. Sony showed up and showed how to do it and that was it.