I have been using a high $$$ UV filter on my L lens, just because I would rather scrath it than my lenes glass if I should walk through a bush or something and not paying attention ie, watching the wildlife I am trying to shoot. I have not had it happen, but with my luck, if I take it off I will.
I do think it helps with birds in flight with the skies.
I thought so, too, at one point, which is why I have a $200 UV filter gathering dust on the shelf.
. Digital sensors already have UV filtering on them, so adding an extra doesn't do anything; and the lens elements are MUCH tougher than you'd think. Unless you jam it against a large stick, brushing...brush against it won't hurt it.
That all said, if it makes you more comfortable to have one, and aren't seeing poor IQ because of it, there's nothing wrong with using one.

