"so while DNA testing may give me a few surprises, it isn't helping with my family tree in all probability, or would it?"
It might, and it might not. It's not a substitute for the kind of research we're all doing, but it could supplement it. Someday there may be enough people who've had their DNA tested that it will be possible to simply plug yourself into a giant worldwide family tree. But what will be the fun in that?
Star explains, above, how her husband has found it useful. In some ways it's a bit like those little green leaves in Ancestry.com. None of those leads are a sure thing -- they all have to be investigated -- but they might lead somewhere useful.
And even if you don't find it helpful in your genealogy research, I'm certain you'll find it interesting. It's a whole different area of genealogy work.