It's extremely difficult to find a system that can have very low to no fees and that isn't simultaneously open to abuse by a script-kiddie... unless that system doesn't actually store a ledger but rather something like ...balances which shift.
Actually even then you can spam it by creating a lot of balance addresses that would require XX bytes to store, just by sending a no-fee tx of 1 satoshi duff to a veeeery long list of random addresses. So, I really can't think of how you can make a promise of zero to very low fees and infinite scaling when you are also opening yourself to an attack vector.
But then again, I'm not the coder here.
The difference is our nodes are paid well to run high end equipment and have big pipes to the internet. That is why an attacker would be wasting his time and money, as it will have no effect. The transactions would merely be absorbed. The only reason a block size needs to be protected is when you have volunteer nodes that will drop away if it becomes too costly to run them. Currently, most Bitcoin nodes are not normal people but big businesses hoping their investment in Bitcoin will pay off when they get to run those LN networks, because someone has to do it, they're centralized. I'm sure the fees will become profitable, and in order to make these separate "networks" (actually holdings by an escrow agent) transact with each other, you will need them to act exactly the way Banks act today, and thus Bitcoin simply becomes an asset class for just another mechanism in the Banking Wall Street world. Nothing to see here, move along. nothing changed, Bitcoin was absorbed into the Borg. Thank God for Dash.
