This is pointing out something profound. Investing is powerful when you can have liquidity right away.
AN ASIDE: The valuation in the ICOs too high. But the following profound point still holds true...
Imaging if an angel investor can invest in a company early, like Dropbox. Then when it grows some, he could sell 10% of his shares on a highly public and liquid market (like Ethereum coin exchange). He then invests that in AirBnB when it was tiny. He may invest in a startup that goes down after the Series A. Oh well, he may sell for 30% the valuation he invested in. The power is there by those who make big gains in the big winners, and that they can then move money out very soon and into new places.