The Signal app has integrated MobileCoin, a shitcoin.
Cashu sat is Bitcoin ecash sat. 
Discussion
MobileCoin is obviously shitđź’©.
But they don’t know how to integrate independent and sovereign bitcoin payments.
I agree that cashu would be much better compromise thou..
Signal probably doesn’t want to integrate Bitcoin payments, rather than not knowing how to.
MobileCoin is so awful. I think the Signal people would admit it was a huge mistake.
Cashu is permissioned shitcoin where mints can and will rug users ! People should use lightning instead and if they care about privacy there is still joinmarket, and other hops like swaps etc.