Enigmail is a utility that permits email encryption: it is an addon to the Mozilla Thunderbird email program.
Who uses enigmail? Is it mostly used within a single business or between friends and family? Or is it used between businesses? AFAIK, banks don’t publish their public key (if they have one) and they don’t ask their customers for one.
Obviously, few financial institutions want to get involved with configuring their customers’ computers. But why is there so little interest in creating secure email? I suppose there’s a chicken and egg problem.