Is it cool for a 33 year old bloke to wear leather jeans? I want to buy a pair but need advice. Is it stylish? Or a fashion no no?

Buy them. Only wear them where you feel comfortable wearing them.
I found this pair

Classic Loose Fit Men's Leather Pants by Xelement

Is it smooth leather or sueded leather? Smooth leather is very casual. Sueded leather is less noticeable. I used to have a pair of sueded leather jeans and just loved them. Only one problem with leather jeans - they don't have ANY give at all. Zero. Unlike cotton jeans they don't give so if you gain a little bit of weight they won't fit or you could split the seams out.

Some gals think they are sexy.

WARNING! Before you wear them watch the "friends" episode where Ross buys leather pants, lol it's a good one and it will give you some insight into how leather pants work on a man!

Good luck!