> Though here is the definition from Merriam-Webster, which
> I'd consider the standard reference for US English.
The nuance is sometimes important, M-W was the first dictionary to give "figuratively" as a definition for the word "literally" due to the way some people use the word "literally" online.
I also think you'll find a lot more organizations that use MW as their reference standard than other US dictionaries.
Prescriptive: Describes how language should be used.
Descriptive dictionaries are highly favoured by those who like to effect change (I'm deliberately avoiding the word Liberal because I'm not in the US and I understand that word to be politically charged for many HN readers). Prescriptive dictionaries are more favoured by those who keep traditional values. Descriptive dictionaries can be used to say "I'm using the word correctly" and prescriptive dictionaries can be used to say "you're using the word incorrectly".
any of the five terminating members of the hand : a digit of the forelimb especially : one other than the thumb
That seems more correct to me because I don't think in normal usage saying that "most people have 10 fingers and 10 toes" would be considered an inaccurate statement. And, if someone said they have four fingers on their right hand, you'd assume they meant they were missing a digit.
And even the Collins dictionary has a countable noun meaning with the usage example: "The fingers of a glove are the parts that a person's fingers fit into."