Hello, I would say it is VERY important. mark your knives if you want to sell your knives. There are a few good etchers on the market for under $100.00 that will do the job of marking your blades. and Ernie Gossip is the best stencil maker I know.
My reasoning for this answer is simple. Its not a matter of if someone will want to know who made the knife.. its more a matter of WHEN then do, will they be able to easily find you and contact you to place a order. Then there is also the pride of making something and signing it for lack of a better way to describe it. Like a Artist. I sign my knives. by stamping them HHH..
Some may say thats not enough.. And will tell you you need to put your whole name and even the city and state where you live.. I dont disagree totally. Once upon a time, not to many years ago. We lived in a world where stuff was simpler and the world was much larger.. Back when we only had 3 TV channels and a cord on every phone.

Thats when I think it would of been important to have as much info on your blade as possible if you wanted to sell knives. But in todays INFORMATION world with GOOGLE search and the internet, etc. Using just your name or initials alone if enough. Dont believe me, Google HHH and the word knife or folder, or filet, or kitchen, or hunting knife. etc.etc. and see what I mean!

You will easily find me and my info.
God Bless