Paid hosting over paid forum software are both entirely two separate things, If I am understanding you correctly.
Paid hosting is always worth it depending on the money your willing to spend. Limitations are cut off and your pretty much able to do what you want (inside the TOS of the service host).
You usually are then allowed to host VB or IPB (But they require licenses) so I am not sure how worth it they really are.
Paid hosting however is always worth it. It has nothing to do with being seen by a search engine, as any site paid or not can be seen sooner or later, it's just about how quickly you work on your site, and pretty much setup backlinks etc.