A button should be nice! Rated 5 out of 5 stars
A button "Open in Chrome" in bar menu should be a good idea!This review is for a previous version of the add-on (1.0.1-signed).
It's been added to the next version, which will hopefully become public in a few days.
Edit: After looking at the Mozilla approval queue and the rate at which its developers work through it, it seems likely the new version won't be available for another month or so. There are currently 138 other addons in queue before this one and at a rate of 4-5 code reviews per day yields a likely target date somewhere between January 6 and 12 next year :(
For the impatient, I've thus made the updated addon v1.1.2 immediately available outsize the cozy and safe fence surrounding the mozilla addon garden. Details in the "about" section of the addon.