The absolute stupidest reason for rejecting Bitcoin:

"Power grids can be taken down, and the internet may not exist."

99% of your day-to-day transactions are done using electricity and the internet.

Where do you keep your money today? Most likely in a bank account?

If every power grid on earth is somehow taken out, I'm 110% sure the money in your bank account won't be accessible either.

And I'm also 110% sure that the Bitcoin network will be back up and running BEFORE your bank.