I've heard this advice as well. It certainly doesn't hurt, if you have credit cards, to prefer them.

I imagine it is a lot nicer to have a fraudulent item on a future bill, than an actual fraudulent deduction from a current active account. And fraud correction is prompt enough, that the bill never comes due on a CC, whereas the money is, indeed, missing immediately on a debit card.

That said, not having any credit cards, I would never open one simply for the fraud protection.

Debit card fraud correction has always been prompt and accurate, for me.

The card companies do not discriminate, currently, between corrections on credit and debit cards. Currently, that's largely thanks to contract language with their debit card customers that prevents them from such discrimination.

I added disclaimers like crazy above, because FinTech is a constantly evolving industry with constantly changing terms of service. And because most people working in FinTech are assholes who want to scam you.

Edit: I've corrected the above advice with yours, thanks! There's certainly no reason to prefer debit over credit for online use, for anyone who has both card types. I just have a bad habit of using the words interchangeably because I only carry debit cards.