I am wondering if technical analysis is really working for Monero and crypto coins in common. Actually, trading with technical signals are only working because there are many people which follow such rules. Are there so much people trading cryptos that this could work?

12h bullish divergence. I'd say Monero at .0019-20 is very good buy for short/medium.
There are MACD bullish divergences regarding the recent 0.00189 low in all the charts between 1 day and 1 hour.
Pretty much all technical analysis is a kind of financial astrology, even in the Forex. So yea, when it works it does so because people are expecting it to work, they trade accordingly, and thus it becomes self fulfilling.
BTC has shown demonstrable genesis for TA, but altcoins not so much. With something like XMR, the trading base is currently far too small for any attempt at TA to be credible. It's mainly used as a propaganda tool, if anything.