Bisq 1 is very safe due to how both the buyer and seller putting bitcoin into a security deposit. This essentially functions as an escrow. If the buyer or seller does not follow the trading rules then a penalty can be imposed and their peer can be compensated.

Bisq Easy is for smaller trades, and does not have the same security guarantees as Bisq 1. It sacrifices some security for more convivence (no bitcoin needed to trade). The security model for Bisq Easy is based on seller reputation. Here are some tips on how to trade safely on Bisq Easy.