Not true! Cryptocurrencies have real-world productive use cases such as money-laundering, ransomware, drug and weapons trade, terrorist financing etc. As well as some less-morally-wrong stuff like hiding from oppressive regimes. A bet on crypto is a bet on the future of these activities.
I think you forgot "contributing to climate change by using as much energy as a small country" which may not apply to ethereum anymore, but it sure still applies to bitcoin
You are on the right track.
There's an incredible amount of word salad piled on the fact that people are playing a negative sum game when getting involved with any cryptocurrency that has transaction fees.