It won't add anything to your airline CV. It might make you a slightly better handling pilot if you are flying a tailwheel a/c to do aerobatics.
If you're looking at flying in the Canadian outback, then it might be useful. If you're interested in agricultural flying, then it's definitely useful.
Why flying a tailwheel a/c might make you a better handling pilot is that you have to be on top of the handling until you've stopped. Once you're flying, it's largely the same as a nose wheel aircraft.
If you're looking to the airlines and in Europe? I wouldn't bother unless you're going to do aerobatics.