Yeah the Somu looks like it would be better, but my current laptop only has USB-C and it doesn't look like there's a similarly flat implementation for USB-C. It's also still an important and fragile part sticking out from the laptop body so I think one embedded in an expansion card would still be good!

Also I've got a Yubikey very similar to the Somu, so I don't think this is a Tomu/Somu exclusive concept. The benefit of Yubikey specifically is that they're approved for certain types of specialist access – at work I am required to use a specific implementation, not just any U2F/FIDO key.