> and there doesn't even see to be a dock on what it supports.

there is, at the bottom of the get started page

currently besides validating the key itself only ssh and git signing by ssh key is supported by them

Also directly from the main page the first noticeable thing:

> TKey’s design encourages developers to experiment with new security key applications and models in a way that makes adoption easier and less risky for end-users.

I.e. it's for now mainly for developers not end users (for now).

There is a "button" on it. (Which yes isn't mentioned anywhere, outside of some article you can navigate to by following multiple links).

Most important (and they could be more clear about it) it doesn't have (writable) persistent memory. Which has both some grate benefits and but can also have some major inconvenience. And depending on how/for what you use smartcard support I'm not sure it might ever support it.

Anyway the shop opened around 16 days ago so it's still very early days for TKeys (and their website, and documentation, etc.).

I'm looking forward to what it will enable.

But AFIK it's already a grate choice for certain kinds of companies for their employees.

There is a touch sensor that detects touch events. The signer application (used by the SSH agent and other things) for example detects user presence by waiting for a touch event before performing the signing operation.