There is no guarantee that it is 1:1. I can send Bitcoin to a mint to create ecash, then withdrawal the Bitcoin from that wallet without effecting the amount of ecash. Then it is backed 0:1. You can s...
It’s not perfect rn it’s a brand new layer 3 . If you did what you said your ecash would be unspendable until there were sats in the mint. For now I would not accept payment in ecash directly I would post a regular lightning invoice and the payer can use ecash to pay the lightning invoice.