The feature needs to be discussed and may not be popular as such action will delete previously copied text. Imagine copying text from a page and you want to paste it in another page and accidental mouse text highlight (or select to replace) will delete the previously copied text.

That you for you kind words. This extension does not have a toolbar icon since a toolbar icon without any functionality is just a waste of space ;)
If in future, there is a need to have some functionality via toolbar icon, I will add it.