The OP states he just got a metal etching machine... I'm guessing you put the piece in place, throw the design on the computer, and it does all the work. Sounds like a certain amount of just wanting to play with the new toy!
I'd say go for it - whatever trips your trigger, blows your skirt up, or makes you happy. For personal use, it seems like a good way to identify your tools. As for resale value, I'm sure that I've destroyed the resale value of a lot of my tools by grinding on them, heating up and bending them, using the plasma cutter, or whatever else I've done to make them work for me... Heck, they're tools - not collectibles... Don't get me wrong. I take good care of my tools, but the last thing I have on my mind when I'm using them is that I'd better not hurt their resale value...