I have honestly lost track of the amount of software I've seen in the past 20 years, that people insist they absolutely must continue to use despite its well documented gaping security flaws. Because it has a better UI or makes their life very slightly more convenient in some way.
Versions of Microsoft Office from the early 2000s where an entire operating system could be pwned simply by opening an excel or word file with malicious vbscript in it were good examples. JPG parsing buffer overflows. People continued to not only not patch it, but use it in its out of the box configuration.
For reference, organizations that have now banned Zoom include google, NYC public schools, SpaceX and NASA.