I like having the AB button on my browser but it stands out like a sore thumb. For example, in Edge, every other icon is made up of a single color and the design seems to be a type of outline.
AB is the only icon that is bright red. Red tends to signify danger or warning or something that needs my attention right away. Which should not be the case when AB is simply sitting on my address bar.
It should fit in better once you install other extensions with their own icons; IMO this scheme lets the user know at a glance that this icon is not part of the default UI.