The reason I practice it is that I almost always dive solo and rarely below 30 feet these days. I don't look at it as a means of escaping an OOA situation, but as a means of getting up should an unlikely "catastrophic" equipment failure occur (ie. hose ruptures, reg doesn't free flow that one rare time, etc.).
I see no disadvantage having it in my tool box. Of course you never hold your breath, but that's a given.
I've never had an ear problem surfacing several times (CESA or not) from 20-30 feet to check location (and I usually do this on most dives). But, everyone's ears differ.