How much should a project worth in terms of crypto marketcap?

Let's talk about the bubble that everyone talks about, and let's zoom in to the opinion that most coin marketcaps are overpriced by 20x due to projects not being delivering real value as of yet.

There is one problem with that though, there is no exact science to evaluate a project's value base on it's coin's marketcap, yet. Cryptocurrencies are not stocks. In stocks, we might use the P/E ratio to determine whether a price is overvalued.

Cryptocurrency is not a stock, and neither is it 'forex'. You might be able to trade the value of EUR to USD, USD to JPY, and just about every currency. You can't do that with crypto. In my opinion, it is a hybrid that no one has every seen before. It's value is indirectly tied to the performance of a company (kinda stock-like), and yet it's a mode of exchange as well (a currency). So is there even a good quantifiable way to say that a company should be worth this and that much of its coin's marketcap?