Ok, seriously??? (You have a real knack for bringing up this kind of stuff. lol)
About prostitution? It's really more of a discretionary thing and whether or not the authorities want to enforce such a thing. I would think this is a rather horrid way to live but maybe some of these people have no other way to live. Out in NV there are bunny ranches (whorehouses--similar to prostitution) and it's legal, though honestly that doesn't mean there isn't "pimping" of sorts going on behind the scenes. You just probably never see it.
So far as porno...After awhile watching it just gets boring. Seen one, pretty much seen 'em all. Leaves your conscience feeling filthy once the fun is over, and not in the good way either. Call me prude nowadays, but I got sick of it and haven't gone back to it though I'll make a joke once in a while. I'm pretty indifferent about it personally.
I suppose this is an area where I'm a libertarian b/c I don't care what goes on behind closed doors that is consensual or what you watch for the most part (provided it *is* legal)--don't wanna hear about it.
However w.r.t. the legal part of things for both areas:
In porn there is as least some (admittedly patchy) semblance of screening, checkups, and licensing. If filming is to be distributed professionally and commercially, much like any other part of the film industry, it *has* to meet certain standards like making sure all involved are at least 18 years if age or older at the time of filming. I'd imagine hentai and cartoon "porn" is a legal gray area (it isn't exactly human), but I haven't checked on that (feel free to knock yourself out).
Whereas prostitution pretty much is "How old are you? Do you have I.D.? Are you clean? What's the going $$$ rate?" and it would seem nobody cares after that point, at least until someone gets hurt.
If you're asking a comparison between the two, there's probably not much difference. If you're worried porn will get banned, don't. For a dying industry it still rakes in quite a lot of $$$ and there will always be a demand for it, I'm sure.