You're forgetting about hacked PayPal accounts with bank accounts linked to them. Echeck may clear but what do you think happens when the owner of said bank account notices charges?
It's not safe.
I dint take into account this possibility but since echecks take 5-7 days to clear, it may just reduce the risk of getting chargedback. But still there are possibilities of the transaction getting reversed till 180 days.
i suggest you avoid dealing with dodgy people that offer Paypal as the payment method at all costs, even with PP mycash or PP echecks. Your problems will go away automatically.
There is always a way to chargeback with PP... So really be careful.