First of all, I'd have that info in digital form if I was going to document RTs to this extent.
Secondly, I find trying new RTs on a given track much better in RB, where I can keep the original (just mute it) and generate it again on another blank track .. and another .. then 'comp' the bits I like from each to another final track.

As for having 50 BiaB files for a given song; in RB every time you save a SEQ file, it creates a backup file, so you always have the previous version, and the one before that.
How many you have is controlled by you, as is how much disk space you want to allocate for them, and even whether to delete them or put in recycle bin when the quota is reached.

There are lots of such 'hidden' reasons I like RB/PT.
I've had friends ask me to come help them figure out how they messed up a tune.
The ones that used RB/PT are easy. I just ask "when was it last OK?"
reply - "Tuesday night"
my response - "OK let's just go back to Tuesday night".
I restore the backup and 99% of the time everything is great.

The fact that RB does backups, and uses a 'Temp Audio Directory' to facilitate Undo/Redo are two huge reasons I prefer it over BiaB.
The available extra tracks, ability to generate just sections of a track(s), using Multiriffs to hear a bunch of variations at once, and the Time Sig/Tempo advantages make it a no-brainer for me.

I agree this far; rough out an idea in BiaB (faster), but when you want to get surgical, add additional audio/MIDI tracks, and still be able to Generate RTs, I prefer RB at that point.
Niggles? Sure .. mainly because it does things other programs can't do, so you have to get used to the workflow.
As a comparison, Photoshop can do awesome things, but it is NOT intuitive right off the bat. You have to learn to use it.
Once you do, you can compare others to it fairly, but until then, you simply don't know.
RB is that kind of tool; it does things no other DAW can do, so it may seem to have 'niggles' at first .. though I'm not 100% sure I can actually define niggles ..

Make your sound your own!
.. I do not work here, but the benefits are still awesome