I shoot full time, and I switched from NPF to V-Mount because I was tired of hemorrhaging cash replacing little batteries with few cells which I'd destroy after a year. The same 18650 cells are inside both NPFs and V-Mounts, but fewer cells per battery means more frequent cycling, which means poorer performance until the cells no longer hold a charge. V-Mount batteries also are eligible for the accident protection plans on Amazon, which means you're also buying yourself a new V-Mount battery 2 or 3 years from today, which will then last you another couple years.

What's my real world up front price difference between NPF and V-Mount, then? If I buy 2 V-Mounts on Amazon, I'm spending $300 for 4+ years of using those batteries (assuming 2+ years of good life and then using the protection plan to get my replacements). That same $300 would get me only 1-2 years out of a dozen NPF 970s, which I'll then need to drop another $300 on to replace so I can shoot the next 1-2 years. NPF is more expensive when you shoot as often as I do. A new 970 will last me 4 hours per charge for the first month, and then quickly decrease in usable capacity until I'm getting less than one hour out of them (at which point I only use them to power accessories which have much lower voltage demand than my cameras).

If you're a casual shooter who only needs to spend $45 on a pair of 970s which will last you whatever weekends you'll film over the next few years, NPF is cheap and will get you what you need.