I do something similar already, where I never carry around the debit card associated with my primary checking account.
You have awful fraud protection and zero to near-zero rewards.
Banks will give you net-30 terms for no cost, reward you with many benefits, and give you fantastic protection from thieves AND retailers.
Maybe debit cards are a bit better at security than "oh let's copy this number and put a fake signature on a piece of paper"? Even the mag-stripe version of our payment system that we have had here since '79 required online PIN verification.