Almost nobody needs Provoice. It's an outdated radio system type. I think there are less than 2 dozen systems nationwide. That add-on is a waste of money for most people.
It won't add any value to the scanner either, since whoever you sell it to 10 years from now won't have any use for Provoice either.
DMR, on the other hand, is a lot more useful. Some public safety agencies use DMR, but mostly it's used by schools and private businesses. Ham radio has local, and nationwide DMR radio systems as well.
NXDN is also used by some public safety, hospitals networks, schools, and private business also.
There are statewide, and multi-state DMR and NXDN radio systems that businesses (think: taxis, busses, dump trucks) can lease the rights to use, also.