FWIW, the precedent is Smalltalk, and especially ML family languages such as Haskell and Elm. All those use commaless argument lists, and the latter treat certain whitespace as a significant delimiter.
I suspect 80% of this unusually aggressive review thread — all the opinions about whether commas help or hurt readability — could be replaced by a poll that asks who is familiar enough with one of those existing no-comma languages to be used to looking at it. Which I suppose is fair: we don't want the language to feel too unfamiliar to its user base. (I tend to think half of why Java took off where other contemporaneous high-level OO languages didn’t is that it used curly braces.) Still, there’s little use in arguing out rationalizations for familiarity bias.
(I don't mean to dismiss the concerns about confusing exceptions to the rule in func decls and .-prefixed expressions. Those are a different beast, not just a function of familiarity.)