once we start operating off the block chain, then we are open to security issues. keep in mind that a new or casual user these days or a "commerce" user in the near future does not know enough about the way bitcoin works to not get taken advantage of.
In part (as far as I understand LN and other similar proposals) I agree. There are more things an user must know and evaluate when using these off-chain systems than with regular on-chain transactions.
But in my opinion, LN and other off-chain methods are still suitable if you use them for small micropayments (everything less than 5-10 USD). Most people in first-world countries could afford to "risk" enabling a LN payment channel for, let's say, 100 USD per month. It would be like a prepaid card, and for potential scammers there would be probably not enough incentive to attack single users. (If there are attack scenarios that could affect multiple users at the same time, that may change, though).