When has mixing up which "there" to use actually mattered to comprehension in the real world? Grammar is not a neutral, it is often employed as a weapon to enforce class divisions along perceived differences in education for one thing and so I think it is valid question.
Grammar is a construct and concept applied to language in retrospect because it makes some people anxious that language could have arisen organically without needing a rigid system of rules with names.
It is a pathetic and hateful choice to not bother to see value in your words just because you mixed up a word in a trivial way.