Me neither but, then, how many snorkellers take close-up photos of fish, corals and stuff?
Weights allow you to descend easily and:-
1 - maximise your dive
2 - approach the fish on 'their' level
when they feel least threatened
3 - stop shooting to the surface as you pause:-
a) - to focus the camera to take the shot
a) - to compose the shot (at least a bit)
4 - photograph the fish from their 'best' angle
- which usually means not from above
Of course, weights mean you surface slower!
Using weights, and if so, how much, are your decisions.
If I could find a safer way of
dealing with buoyancy, I would ditch weights.
Weights have to be applied gradually, one at a time, until the buoyancy is right.
Positive buoyancey at the surface is a must.
Negative buoyancy is dangerous especially as your buoyancy decreases with depth. Positive at the surface
turns negative as you descend.
Use the quick-release clip on the weight belt if you feel at all uncomfortable. The belt does impede
your swimming and you are more important.
It's worth paying a bit more for a belt with pouches for easier adjusting of the total weight.
If weights seem unsafe, don't use them.
Turn your shutter speed up for a better chance of a sharp shot even if you are moving.
Look for subjects where being on their level is less important. There is plenty of different stuff
to shoot down there.