Half the addons I use, I don't even know what they are doing, or duplicate other addons and have been installed since before MoP, I'm bad about installing addons and forgetting about them.
As for how I tell what Carbonite is doing / not doing, at this point I know almost inside and out what it's doing so I can quickly test parts or examine it. I also keep a standalone version of WoW installed with nothing but Carb, Prat, bugstack and buggrabber so I can quickly test if a bug I see is caused by other addons or not.
Incentive to fix stuff, I've always got incentive
and breaking apart the addon like it has been provides me even more as it allows me to do things I wanted to do like updates to warehouse to add auto-repair and auto-sell which I never did before because Carbonite being one large do everything addon meant adding more features added more bloat to the people who didn't want it. Once it's released in the new have it your way aka "install what you want" I can justify it. Adding auto-sell won't impact anyone who isn't using warehouse. That's just one example.
As for the git version, yes it's now at a point it can be used. The 2 main things it doesn't have, 1 is for level 100 characters only, and warehouse doesn't yet support the reagent bank.