@NathanG - In my opinion, these distinctions are made for investment purposes. Investors or banks want to look at a balance sheet and see if you’re worth investing in.
To that end, I prefer the holistic capital maintenance approach which takes into account physical and financial capital. A company that pays back both physical and financial capital is very attractive indeed. Every dollar in earnings then is pure gravy.
There are not many businesses that operate on this margin, from what I can tell. Most businesses just want to show that at least they're servicing debt on their existing capital requirements.
But when profits are squeezed thin and the economy is tight, being able to show that you are, for all practical purposes, in the black on your capital repayment, makes you an attractive company for investors and even for other potential suitors in the case of a buyout.