I don't have enough linguistic background to understand the distinction, but I've also heard that using "will" for "intent to do something in the future" is somehow linguistically unusual because previously that job was used by "shall".

Sorry I can't give more details, I forget what the actual distinction between the two is. I just recall that it apparently creates difficulty when English speakers learn Romance languages that still have their equivalent of "shall".

Edit:

Apparently, the distinction can either be a lot more relevant or a lot less relevant than I thought depending on the context (e.g. legal text vs. everyday speech).

https://en.wikipedia.org/wiki/Shall_and_will

It's interesting how much of language is invisible to a native speaker. If you had asked me, I would have said that most people never use "shall". However, now that the article points it out, I realize that native speakers use "Shall we <verb>" all the time.