Max. you should put on LN is $500 and that's if you are a risk taker. Normally $200 would do great. If you are putting 40k on that thing you are insane or dumb or both.
You could use these analogies:
How much cash do you take with you in your wallet? $500 max really, anything can happen, and everyone can see the giant stacks of high value bills every time you open it if you do
How big a credit card limit do you agree to when it's 1968 when credit cards are brand new? Not so big, it's new tech, and you're responsible for the tab if anything goes wrong
So when it's one new form of tech (Bitcoin) with another riding on top (payment channels),
AND everyone tells you it's inherently risky too, well, I'm not sympathetic to this person, let's put it that way
Damn, I just had to give you 1 merit for that answer, because it was 100% spot on.

As a previous victim of credit card fraud, I can tell you that credit cards and debit cards are more prone to losses, because they only need to get a 3 or 4 numbers at the back of your card to empty it.
I recently also had a friend who got his debit card stolen and someone just used the "tap to pay" function and tapped it 9 times without the need for the pin and withdrawn a large amount of money. <They have a limit of $20 on tap payments, but you can tap it a lot of times within 24 hours, before the card are flagged.>

--> He only realized that the card was gone after a few days has past.