Fitt's law is useful for two insights: The obvious one is that things you want to be easy to click should be large/close, but the less obvious one is that things you don't want to be easy to click should be small/far.

The "..." dots is probably an example of the latter - I'd guess that Google wants people to view entire conversations by expanding the conversation view, not by clicking "...", so they make one way much easier than the other.