Yes the point is exactly this.
Many times the "main" problem is documentation.
(I've not your experience, but as I've started to program with a Commodore 64 when I was 16yo, we could be considered "old generation" programmers, where you have to read a multipage manual to start to use things.)
Please don't give up and maybe bring this problem with maybe your proposed solution in "Open Discussion" or "Developer forum", probably opening a "clear topic" about "expressions and units" would be useful.
I've had a proof when I've opened a topic about something and now it is became a very interesting discussion and some "clever people" are pointing put the problem and hopefully find a solution. Sadly the discussion has gone beyond my knowledge after some posts when the discussion was about "internals and algorithms" .
But if this will improve FreeCAD I will be happy to have "started things".
Many times people came here only to complain, so having a "plain discussion" with people is difficult these times.
I'm also happy to make some discussion with users that will not end in ruvid sentences.
It is difficult as many of us are not "native English speakers" and probably we have not a "very educated" way to say things, so some "highly educated" peoples are hurt by our ruvid sentences, even if they are not intentional. (not every time sometimes they are very studied ).
I stop here, as I will be guilty to do "too Off Topic" discussions.
Kind Regards
Carlo D.