Thanks Joe, interesting, for some reason, my brain was thinking main reason for the bootable was an easy recreation of your Mac HD,..

1- but that can be done if not bootable right?

2 - The real point as you state is to run repair, but since invention fo the Recovery drive that is less important now right?

3 - Other OS is not important, except for my old copy of Dreamweaver and I use Parallels for that. And being that I just renewed that at $50 per year ( still way better than subscribing to DW new with Adobe which is $200 year); maybe I don't even need parallels with a bootable back up.. since I'm using El Capitan with Parallels?

I guess Parallels is nice as you don't have to do a full reboot, which is a pita,