Yep, I use several MA's and a double sto to filter signals but they do not serve as signals, simply as support for price action. I find this easier than pure price action...to each one's own. The only arbiter is that one's methodology works or it doesn't. A derivative of price is simply that. For some of us, derivatives can help define momentum dynamics across time frames and fine tune geography for safer entry areas.Clearly they're not "needed" for successful trading, in that many people are trading successfully without them.
I'm just acknowledging that there are also people trading successfully with them ... but (in my opinion) those are all or almost all people using price action as well, whether they admit it openly or not!