Hard to say (and I've not tried the Pro version myself), but the website describes the differences. More campsites, mo ads, better filters (elevation, for example), bigger maps, etc. Whether that has value to YOU is harder to say. If you usually find what you are looking for on the base version, I guess the answer is No. But if you like more convenience or narrower search results or [whatever], then maybe its Yes.
I've heard you can get a refund if you cancel early, but don't see anything about that in their site.
https://www.allstays.com/DL/