Shame I have to pick EITHER 2-step or Security Key.

My ideal would be to use Security Key to bypass 2-step on devices that supported it and then use 2-step elsewhere.

For example, some public computers have the USB port literally glued shut, therefore Security Key won't work. In those cases I'll still have my phone with me and could bypass it via 2-step.

Essentially I want to use the Security Key as a way to save me typing in my 2-step code because I'm lazy, rather than to "add" security.

Google's current 2-step "remember-device" doesn't really work for me as it utilises cookies which get cleared. I could add it to a white-list of preserved cookies but they use obscure often changing sub-domains.