Altcoins Instant is a type of payment account on Bisq that uses cryptocurrencies to settle BTC trades within 1 hour—meaning the buyer must send payment and the seller must acknowledge it within 1 hour.
Ordinary Altcoins accounts have a trade period of 1 day. Altcoins Instant payment accounts are identical to ordinary Altcoins payment accounts in every other way aside from their trade period.
Only use this payment method for making or taking offers if you know you'll on your machine while the offer is available. Disable it other times to avoid disputes.