To me, the importance of mathematical grammar comes through in that the statements of mathematics have to be precise, and it is difficult to achieve a high level of precision unless the language is free from ambiguity.
To make my point clear, let me use a very well-recognised sum: “Two plus two equals four” and try to explore its grammar. It contains nouns - “two” and “four”, a verb “equals” and a conjunction “plus”. The word “plus” gives the same meaning as “and”. Now if I use another sentence, for example, “3 and 5 are prime numbers” it’s possible to form an analogy between “2 plus 2” and “3 and 5”. How will the brain interpret both sentences? Similarly let’s examine the role of the word “six” in a sentence, for example, “This section has six subsections.” Unlike, “two and four makes six”, “my car is six years old” and “look at those six buildings” etc. Another word to consider = “is”. Let’s consider three sentences: “5 is the square root of 25”, “5 is less than 10” and “5 is a prime number”. In the first case the meaning of “is” is “equals” which is not the same in the other two sentences.
Now if I try to write the first sentence mathematically - “2 + 2 = 4”, there is no ambiguity or vagueness. Mathematical sentences can also be highly complex: if the parts that made them up were not clear and simple, then the unclarities would rapidly propagate and multiply and render the sentences unintelligible. Mathematics grammar provides the required clarity. Just the same as in other languages, many of the sentences of advanced mathematics have a complicated structure that are much easier to understand if one knows a few basic terms of mathematical grammar. So if you want to get to grips with maths, grip the grammar of maths!