Hi! Well I can tell you that on Illustrator (at least for me) creating pretty rendered pieces is a pain and I feel it limits you, of course it has it's benefits but I would choose PS over it everyday. It is worth it if you are working on a tshirt design or a cartoon series that needs to blowout each piece, and it doesn't lose quality (which was what I made this piece for), or maybe your style requires vectors, but beyond that I see no other mandatory uses. If you still really like it, go for it! You could even use both too!