The momentum of cryptocurrency exchange-traded funds will not slow down after the launch of Ethereum-ETF, believes William Quigley, co-founder of Tether and WAX. On the contrary, he is confident in Wall Street's "greed" and that it can ensure the emergence of new altcoin-based instruments.

The stock market loves "the next hot new thing." Every time Wall Street launches a new tool to sell to consumers and it's a success, you can be sure there will be copycats.

Quigley believes the "ETF mania" will last until there is a big pullback, after which some of these funds will "close due to lack of demand."