I used VFR Fight Following back in the day quite a lot. Was very handy when transiting high density traffic areas, and of course, they hand you to the next controller if required.
ADSB has the same sort of limitations as RADAR. Unless there’s a station within range, it’s useless. Yes, these days you can get ADSB-IN/OUT instrumentation, but not many planes have that feature. If you’re using an EFB, it’s useless unless you have phone coverage. (Unless my understanding is way off the mark).