If prostitution is simply defined as providing sex in exchange for an item of value, how is it different from marriage and half of all other relationships out there?
That's OT, but this is your thread. hehehe. Marriage and relationships are different. Prostitutes do not have a long term relationship with their clients, even if you are a regular customer.
Except for high end escorts, I don't know of any prostitutes that give credit or terms of payment that extend beyond the encounter.
As for "legit" uses, I'm accepting donations to feed children. uh,, not trying to hijack the thread okay, just giving an example.