“Is there a difference between a sugar baby & a prostitute?”
A prostitute will generally meet with any client that calls and it is a purely sexual exchange without connection.
“Sugar dating” is usually more similar to regular dating within a particular pool. Generally women on the site are looking for the most fun and attractive date who must also take care of them. Same thing as men who want an interesting date but only will date a woman who MUST meet a certain age/look.
Wealthy men historically have given their attractive girlfriends an allowance to maintain themselves and make themselves more available so this openly facilitates such an arrangement.