You are batting down strawmen Wilf.

but why use OODA?
Strawman. You don't "use" OODA in the manner you are talking about. As zenpundit has already point out it is part of a knowledge gathering, thinking, and doing process. You are already doing it right now.

What does it tell us that normal observation and use of empirical evidence does not?
Equivocation fallacy. Boyd modelled the loop originally on the scientific process. So it is empirical. You are equivocating.

If is a good analytical tool?
Strawman. Analysis is inherent to thinking and part of a person's orientation process. It isn't an analytical tool. Analysis is inherent to the person doing the thinking. It says nothing about the OODA loop.

More to the point, and IMO, the idea that you can be "inside the other guys OODA loop" is neither useful or correct. It implies that speed is an end in itself and this is wholly false.
From what premises are you drawing that conclusion? How do you go from:

(p1) A person is operating inside another person's OODA loop.
(c1) Therefore speed is an end in itself.

I'm missing the extra premise you left out. Perhaps you can illuminate the unstated premise.

Speed only serves your purpose in that it creates surprise. Speed of process is merely that. Speed of bad process creates defeat. If you learn and adapt faster, then great, but you must not die while doing it.
I have no idea what you are on about here. Definitely a strawman though as the OODA process is exactly that. If you get it wrong you are stuffed. That is one of the main points behind it. To try mess with the opponent's OODA loop.

If you are telling me that the OODA loop is just one of many loops used to describe various processes then OK, but it is not the Core Functions, which is how people want to try and use it, and no where near as inherent to true military doctrine.
Strawman and No True Scotsman fallacy.

Try again.