A voucher that is redeemable for sats. It does not have a value in another coin it's sats, sats is not another coin it's bitcoin , the voucher itself is only an iou for sats, a promise, there is no swap from one coin to another. Liquid has its own token L-BTC that you can use independently and has its own blockchain. You can buy L-BTC on an exchange. It's a completely different token from Bitcoin. The only rule is that for 1 L-BTC to exist there must be 1BTC locked in Liquid.