For the past year or so, I have been keeping a completely separate "training" logbook from my main logbook, as I have been trying to get accustomed to a doubles-and-drysuit configuration in a lake and some of the FL springs, and my main logbook isn't really designed to record the kind of stuff I want to remember about those training dives. It's just a small spiral-bound notebook, and my log "entries" are as much stream-of-consciousness scribbling as data. I'm keeping track of hours spent in that configuration but not number of individual "dives." Last week I spent an hour in the lake ascending from 40 feet to 30, pausing, ascending to 20, pausing, ascending to 10, pausing, and surfacing, then back down to 40 and repeat.
Not to sound like a broken record, but if you were using Subsurface, you could put those dives in and use tags to distinguish your training dives from your fun dives. Or tags to indicate dives with reefs and/or wrecks and/or sharks and/or fresh vs salt, etc.. You can then filter the display to only show dives with certain tags.
The Notes section will let you enter your stream-of-consciousness blather. ;-)
I haven't played with it very much, but I *think* if you also used the mobile app, you could potentially enter notes about dives while you are actually still on site, even using the voice transcription built into your smartphone to actually dictate your notes, instead of writing or typing.
And, I think if you enter dives in the mobile app, you can have it automatically capture your GPS coordinates, and then when the mobile app syncs back up to the Cloud and you download your data from your dive computer, the DC's logged dives can be married up to the dives you entered in the mobile app, so you end up with one dive that has your DC's data plus anything you entered via the mobile app, plus the GPS coordinates of the dive site (which it will display on an interactive global map within the app).
Don't hold me to any of that about the mobile app, though. I have only used it to pull down my log from the (free) cloud storage and let me look at it on my phone as a reference (e.g. "Hey, what wrecks did we dive in the Saint Lawrence last year?" "Hang on." [whips out phone, looks at log in mobile app, answers question with correct information]).