If this asset class would be trading at $10tn then the concerns would likely be valid.
Why not put a bit of money into the space and let things develop? If you're right, great, you haven't lost a lot. If you were wrong, you made a healthy return that is likely above any other investments you have access to.
I consider this a high risk binary investment -- either it will work, or it won't. Unless you're investing $100k+ (which for most people wouldn't be a small part of their portfolio) you should easily be able to exit positions. This was clear even during the last correction.
From a risk level, (In my view) I'm looking at an angel investment but with better upside odds. The potential upside is disproportionate to the downside, and I'm happy to take on that risk.
I agree with the poster above, BTC and others may be in a bubble but the bubble is tiny compared to other asset classes and previous bubbles.
Familiar with the FDIC?
Limited to 100k, that is extremely low for a lot of people looking for safe asset havens.