Yo tambien. I have my SMB and finger spool in my BCD pocket on every dive, and on one of the first dives on every trip I deploy it from 20+ feet at the end of the dive to brush up on the skill *; I tell the DM on the boat before the dive that I will be doing it do it so that he doesn't think I am in trouble. I also deploy it any time I will be surfacing more than about 20' from the DM.You're not on the right boat...or just didn't notice.
I'd say that about 35~65% of the divers on Aldora, 3P, and Liquid Blue have a DSMB. I'd agree that maybe one diver launches a DSMB every other dive, because that's exactly what I try to do, to keep in practice.
Another reason I carry and use an SMB is that once it is deployed I can ascend to my 15' mark on the string, control my breathing so I am a little negative, and hang from the SMB like a subway rider for the safety stop.
* It isn't all that hard but it is a skill and it needs to be occasionally reinforced. Don't wait until the first time you actually need to deploy an SMB to attempt it.Tip: if your SMB is the type you blow into to inflate it, put your reg in your mouth immediately (of course) after inflating your SMB but do not inhale until after you have released it, especially if you are already at your safety stop.