Cashu is placing trust in a single entity so that is very risky. Fedimint is placing trust in multiple parties. It’s a little better but there could still be collusion. The whole point of bitcoin is to self-custody. If you have the means and technical knowledge to custody your own funds you absolutely should. If you don’t, then start reading and don’t stop until you understand it.

ECash was before bitcoin, but bitcoin is the current winner. Saylor says “you don’t sell the winner to buy the loser.”