You have to do PoW when submitting a transaction. So DDOSing will not be trivial.
But the PoW is for small IOT devices right? Or at any case it is for regular users, and does not take them minutes to compute. I cannot see how that is resistant to an adversary with dedicated hardware.
> You have to do PoW when submitting a transaction.
Then there is a price; it's just measured in watt-hours of energy spent instead of denominated in cryptocurrency.