Is there a taboo on this feature?
Just create a custom template, in which you set the font of Default cell style; you may set the created template to be default (=use when you create new files without explicit template selection).
There’s no reason to introduce a configuration that would in fact duplicate the functionality available through using templates.
If your question implies some omitted information that would clarify your intention, then please consider mentioning it by editing the question.
The answer should be in the settings, not in the manipulations.
… should be …
Ah sorry, I didn’t know where the answer should be. I would be grateful if you also tell the logic behind that statement.
Note that LibreOffice is built around the concept of styles. If you have some prior experience with other suites that are built around different concepts, that prior experience means nothing to LibreOffice.
Writer has a default font setting, it is logical to see this setting in Calc. Does this fit Libreoffice concept?
No. Writer’s “default font” option also changes the styles’ fonts, so directly duplicates the functionality and is redundant. It’s good to not follow that questionable decision to have those settings in Writer.
Will ordinary users ever decide whether settings are necessary or unnecessary?
LibreOffice is meritocracy, which means “doers decide”. And that’s good, because if you think there’s ever such a thing as “ordinary user” you are mistaken. Whatever you suppose to be useful and intuitive, there’s another user who thinks that “product of demented developers” (almost perfect citation). So thinking that “ordinary users decide” would be somehow efficient is daydreaming. Users will never agree on what should be done and what should not. (Even not taking into account that that mode implies that there’s some developer patiently waiting for that “ordinary user” to command them what to start implementing.)
However users do participate in development. Every user is welcome to file enhancement requests; they are considered, and the overall picture of program design is created taking all of them into account (but not necessarily implementing all of them!).
Can you remove this feature from Writer so that there are fewer questions?