Bitcoin and Ethereum are pretty terrible currencies. Proof-of-work is a foundational idea in cryptography, but it’s much better suited for preventing mass email spam than it is as a consensus mechanism.
Not to mention how the cryptocurrency space is crowded with useless AltCoins. Unless you’re an expert in the space, its so hard to distinguish from true innovation and dummies just trying to get a piece of the pie. As a result, you have millions of people pushing things like Dogecoin and Shiba, and it ends up hurting real people.
The way I see it is this: a useful cryptocurrency needs 3 things:
(1) Security (2) Scalability (3) Decentralization
Almost all mainstream crypto fails at (2) miserably, and as a result end up failing at (3). High transaction fees, volatility, low throughput, and energy-intensive participation costs are all barriers to achieving actual utility.