I'm not exactly sure I'd be wearing hiking boots, but each to their own. The difference is drain holes, overall weight, and the quality and type of sole on wading boots vs hiking boots.
Besides, if I'm fishing a $1200 rod and reel, $500 waders and a $400 dollar wading jacket I can spring for a decent pair of boots LOL!
That's not to say you actually need any of that stuff to catch fish. But when you're into a sport, any sport, at a high level one tends to use higher end equipment.
On a more useful note I just grabbed a pair of wading boots yesterday. Not that I actually need them, it's just the price was too good to pass up.
I picked up a pair of William Joseph W2O boots from Sierra Trading Post. Shipped to my buddy in Lewiston who happens to be delivering them right to my front door thanksgiving weekend they cost me $46 all in.
Sierra is a great resource if you're searching for deals.