Magic is creative while law is... not creative.. haha
May be that's why he does it. I work as an accountant, which is very procedural and not creative at all. Therefore magic is an outlet for that creativity.
I have found that a lot of people who work in/study science do magic (I myself have Biology degree) cause it's almost the polar opposite (i.e. Science has rules, magic does not). It's different from what they normally do.
Rev
I see the relation between the sciences and magic a little differently. The creative aspect of magic, the problem solving and method-tweaking feels very "scientific" in nature to me; I think it just appeals to that way of thinking.
John Ramsay was a shopkeeper. Slydini was more of a hobbyist if anything, he spent most of his career performing for magicians, not laypeople. Hence his awful presentation skills.
"you see the coin go? it's because you not watch! you not watch close enough!"