Those investing into a coins using technical indicators to analyze the market before investing should also have some knowledge on fundamental analysis' principles. A bird cannot fly with one wing and that is how it is in trading because technical analysis is not enough to make you, make successful trading and to some extent that is why many investors and traders used both.
Fundamentals is the most important, every trader has to learn about it in every coin they are investing.
TA on the other hand are for traders who like to bet in the market for short term, they need it most as crypto is very volatile, with TA, that could help them a picture of what will happen in the future, if they sees some opportunity in their favor, that's when they initiate the order.
Now, to the question if it works, of course it does, but not for every trader as wrong TA leads to wrong decision making.