Investing in cryptocurrencies is a wild ride. There is obviously a lot of speculation involved but my question is another one: what are good models to evaluate the fundamental value of cryptocurrencies?
One of the best models to value anything is (modified) discounted cash flow. Note that there can be other models, but this is easy, understandable and proven.
Eventually, any value above immediate consumption is discounted future cash flow and its growth. If there is no cash flow, there is no future economic value, outside scarcity that can be artificial (Bitcoin) or true (oil). The trick is that a lot of cryptocurrencies go to the great lengths to mask the revenue share of this cash flow to cryptocurrency holders to avoid pissing off Mr Gary Gensler of the SEC, or any other head honcho regulator.
For example, Ethereum ETH native token will share profits with its owners via its burn mechanics. Unlike Bitcoin which is not a yield generating asset, ETH holders will directly benefit from the transaction fees, which will be distributed to the holders in the form of ETH burn - a somewhat similar mechanism to stock buybacks.
Some tokens have a direct revenue share with stakes. These include Curve CRV, Sushi xSushi, and so on. This could be close to equity and dividends, and a hotbed in securities regulation in some jurisdictions, but there is very little that can be done to stop investors to invest in them. Stopping founders/companies are a different matter but most of the blue-chip decentralised protocols are "unstoppable" - after started, the machine will never stop barring the catastrophic failure of the underlying blockchain protocol.
Some old cryptocurrencies like Bitcoin base their success on the fact that maybe they will be used as a reserve currency and have thus value like the US dollar has today. Today, there is evidence that Bitcoin is becoming attractive to developing nations. However, Bitcoin is not a productive asset and outside its trust value, which comes with its age (trust can be only earned over time), it is not a productive asset. Whereas all decentralised applications built on the top of Ethereum network will yield profit to Ethereum holders.
Furthermore, you can stake your cryptocurrency, like in the case of ETH. In this case, you will put your asset to work to secure the network. The downside is that if you screw up, e.g. by staking with an incompetent service provider or messing up yourself, you get slashed. I do not know if there is an analogue for staking in traditional finance - it would be something like a silent partner in a company, but the forecast of the future revenues are very easy to model mathematically.
If you want to start researching the topic, some of the best sources are venture capital firm blogs that publicly analyse their investments, assets and the investment landscape. I recommend Sigil Fund blog. (Disclaimer: I am LP).
Also, besides the asset being productive itself, you can make yield by borrowing it from the short-sellers for relatively low risk. For example, Aave lending protocol allows you to do this for relatively easily modelled risk (read: low risk).