Placing an offer to sell my BTC and get XMR, it prefill 15% security deposit for both traders and this % is customizable. Why not to set it to 0% if both payment methods (BTC, XMR) are irreversible and why Haveno-reto does not set it like that automatically?
Existing offers of this currency pair usually has 15% or 40% deposit and the fee 1.8-20% which is also weird, I would expect people would be willing to trade like 0-1% just to cover the crypto. fees.
You cannot set an offer without a security deposit. Minimum is 15% of the trade amount. You can specify an even larger percentage when creating the offer.
When taking the offer you must agree to whatever security deposit percentage the creator of the offer has set.
But the idea is that scamming in Haveno is unprofitable (or risky I guess) because you risk losing your security deposit, yes