As a TARDIS it’s a lovely representation of the Pertwee/Baker era flat-roofed, dark door-signed TARDIS, though this one has a much better paint job than the TARDIS of that era ever did. (Not a chip to be seen.) It’s also pretty well in scale with the modern era TARDIS keychain, showing the size differential between the two models, even though they’re made of entirely different materials.
As a keychain I think this would function pretty well, too, as the metal die-cast nature gives it a satisfying weight and sturdiness to withstand the wear and tear keychains often go through. As with all my other TARDIS keychains, I ditched the chain early on. But I have kept the ring, which pokes from the top of the roof lamp itself, in case I ever want to use it for another purpose. It could make a nifty ceiling fan or lamp chain pull, for instance, though is probably too heavy for, say, an earring.