focus on "carrying around" sized money
What is "carrying around" sized money?
To me that means a maximum amount of cash you'd be comfortable carrying around in public (in case you lost your wallet or were robbed). For some high rollers that's thousands or tens of thousands, but average person it's probably several hundred (I'm thinking in USD here)
Yah. Its a convenience and risk tolerance question.
Another reason for LN to optimize for small amounts and focus on "carrying around" sized money. This will also add to risk for centralized pools of custodian-like money to grow too large "off-chain".