Soldato
They do, especially crafting. My first character specialised in crafting first and foremost and my second placed almost as much emphasis on crafting as on their main combat skills. Crafting is extremely powerful in CP2077. You can use it to work a side business as a manufacturer, making a bigger profit from that than you make from being a merc. At the highest levels of crafting, you can make equipment superior to anything you can find or buy.
I think the issue is that the game is easy enough to make it unnecessary to do anything much to increase the capabilities of your character rather than that skills don't have much effect. It's analagous to the difference between 800 BHP and 1500 BHP in a car that's used solely for driving a couple of miles on heavily congested 30mph limit roads in town to get some shopping from a supermarket. You've greatly increased the power of the car, but it has no effect for the use it's being put to.
The reward for exploring is finding stuff. There are a couple of missions, quite a lot of "legendary" items and (most importantly to the way I play most games) quite a lot of notes to read. No direct ingame rewards (although the items might well be an upgrade for a player who doesn't do their own crafting) but for some players the exploration is rewarding. It depends on what you like.
Maybe your right, i never really felt the need to go looking to deep at the crafting as i never really needed to!
Maybe i went exploring in the wrong bits i did take the odd detour down a back alley every so often and did come across a few set pieces that contained the odd decent gun or wedge of cash. I just never got the impression they were fully intergrated with the game unlike the likes of skyrim / deus ex where you could come across an entire side story just by chance.