Aw, I thought it was kind of cool! And since you can mine out a vein on one breath, no big deal. Unless, of course, the beasties in the water are much higher levels than the beasties on shore...
Underwater ore veins are great because they are easier to find in heavily populated areas. Because they will be found only by people who pay close attention to their circle map, there is less competition for them than veins that pop up in plain sight.
The best place for a new character to level up mining and fishing is the tiny opening in the frozen lake west of Kharanos in Dun Morogh (next to the fishing trainer). You can fish there with a skill level of 1 and on a good day a copper vein will respawn a few times in the bottom of the lake. When I was there, I gained +70 with my fishing skill and +12 with my mining skill -- the ore respawned every few minutes!