Dunno, when I'm using email, or any other English word part of our developper vocabulary, like build or bug, I don't feel guilty, I'm just using the words that are used by the rest of my (all-French) team.
But cooking shows, YouTube videos, and basic cookbooks in America use those terms. I found definitions for mirepoix and chiffonade in Better Homes & Gardening cookbook, which is as white-bread American as it comes (along with many, many other French words).
My point was that the culture that produces an innovation ends up defining the terminology because it's easier to use the single term the innovators came up with in their language rather than using long, translated definition for the term. "Bug" instead of "issue when trying to perform a specific action" is not unlike "saute" instead of "fry at high heat stirring or shaking the pan vigorously." I'm not going to say, "jump the onions up."
"Courriel" is the word proposed by the Québec institution (OQLF). It is used in France as well, but not as much as "email", which nobody feels guilty about.
Courriel is also a newly coined word, and an elegant one as well, so it fits right into your "languages are fluid, living breathing things" remark.
Using courriel was somewhat funny and snobbish but people used them to be fun and snobbish, not because the law of the academy mattered to them.
I think we care about grammar a lot more than english vocabulary, and it’s been fading quite a lot the last few centuries anyway.
In French, 'numerique' generally means 'digital' and 'digital' only means related to fingers (e.g. fingerprint is 'empreinte digitale').
I am in favor of using digital in french (we learn to count with fingers after all).