I like this product but I think price is quite not attractive when it costs ~1/4 of Trezor price.
How much does it cost to make one of those?
3D printing in steel isn't cheap, unfortunately.
https://www.shapeways.com/materials/steel - and I do make a markup on top of that, of course.
wouldnt it be risky to put it on keychain as keys in your pocket can damage the qr code?
The keychain will of course wear slightly over time like any other metal object you carry in your pocket, such as your keys. Note, though, that the QR code is "sunk" into the keychain, so it's physical, so to say, not just painted (I enhanced QR readability by spraypainting it, and recommend to do so, but then the paint will be in the grooves, protected from too much wear and tear)
How heavy are we talking about with one of these? (ballpark figure)
I put it on the kitchen scale: 19 g. It measures roughly 3 × 3.4 cm, being 3 mm thick.