yes of course it is still very valuable because with this technique you can find out the right time conditions to buy and sell coins so that you will be easy to get profit when trading.
The idea of using a technical indicator in the market normally is to understand the sentiments on the chart, and can help serve as a good signal to know if the market is ready to move up or have the slight chance of doing so. Technical indicators are good for making decisions but to rely on them, you will need to be mixing quite a number of them and also judging based on other technical analysis on the chart itself.
with momentum indicator, it made it a bit easy for me to understand the market sentiment, either oversold or overbought, how the market his acting based on its price at this point and what decision I should be making. So I agree with the fact that it is not a necessity but it can be an added advantage.
Momentum indicator is very much useful one. Combining it with zig-zag indicator gets me more than 80% accurate over bought or over-sold regions which is the easy identifier to get market reversal information. Without most of here discussed indicators, I could not imagine my trading.