Rated 3 out of 5 stars

This is usually an essential addon and works quite nicely.
My confusion comes from the fact that I can not remove it (no remove button on the Addons page in TB).
It does not work with TB 68 (send button in TB does not do anything when Enigmail enabled, so I wanted to reinstall the newest version).
No remove button in TB 68, so can't remove, only disable. :-/

This review is for a previous version of the add-on (2.1.2). 

I don't think that uninstalling and re-installing would help. Your problem is most likely elsewhere. Please check the following two support threads:
https://sourceforge.net/p/enigmail/forum/support/thread/0023f36d6d/
https://sourceforge.net/p/enigmail/forum/support/thread/d3cf983d0b/