Privacy is a necessary feature in my opinion, but why hasn't Monero become a main coin?
There are many other altcoins that are more popular besides monero, now everyone is paying attention to the main coin, namely bitcoin, because monero is an altcoin so it is not very popular at the moment. Apart from Bitcoin, Monero was beaten by Ethereum, which became the main altcoin of choice for investors.
Let's take a closer look at how Monero is developing this year and it will be bullish again whether Monero will be the best choice.
Monero has a very large community and implement a lot of things. I don't know why you say this coin is not popular, it's just that this project has a different niche. Look, they have been delisted from almost all major exchanges, but the price per coin is still high. I think this project is doing just fine. The main thing is the idea, which was originally thought up by cypherpunks.