Seller just running away with your BTC can't happen, as trade amount is locked in a multisig account. https://bisq.wiki/Security_deposit

The worst part of cash by mail, like any other no-middlemen payment method, is that proving a payment is quite difficult, but even if buyer and seller plays rough, a mutual assured destruction scheme (both buyer and seller lose something) can be applied, so scam rate is non existent on this payment method (maybe also because scammers need higher volume).

https://bisq.wiki/Cash_by_mail

So, if you have sellers around, I would go ahead. What stops me from using cash by mail is providing an address as a BTC seller.