Seems like it's inconsistent across users then. I've been prompted for PIN entry on amounts over $80 with my BNZ Visa Debit connected to Apple Pay as well.
It depends on the terminal and its specifications.
If you have authenticated yourself using the Touch ID on your iPhone, on some terminals you will never have to enter a PIN regardless of transaction value, but some terminals will still require it.
I wonder if those terminals would also accept an $80+ transaction on Apple Watch? I guess they would.
Personally I am quite comfortable for Apple Pay not to require a PIN because Touch ID seems pretty secure.