Depending on the noun, it may not the most idiomatic way of expressing the sentiment it intends to communicate, but that is a different issue. (On the other hand, idiom is context dependent, and the objection here seems to be that it is idiomatic in at least one context, but that people prefer that children exclusively learn some other preferred idiom. But if you don't have this diversity, children don't get to learn and practice context switching as early, and that's an important skill, too.)
I'm going to need some examples here because I'm filling in nouns to that structure and it does not sound correct. "I did [a] water." Huh?
I did a presentation.
The reason I’d suggest not to is because speaking in this way will, in fact, cause people to think less highly of you.
It’s not a matter of principle and “formal correctness” is pretty meaningless in human language, but “don’t speak in a way that a substantial number of people regard as incorrect” is a meaningful goal!
Your claim is really based on fairly absurd notion that a sentence normally used in relation to the kids will somehow set the kid apart from their peers ... who listen to the exact same sentences. As in, the problem of kids speech somehow damaging kids long term is literally non existent in real world.
Miniscule percentage of parents takes offense on it and nobody else cares.
“Aww cute!” responses to incorrect language is how kids develop speech impediments.
Not idiomatic for all nouns, esp those for which there's a more applicable verb.
* I did a puzzle.
* I did a bad thing.
* I did a backflip.
Or, since this is just normal English, it's exactly the kind of thing that ChatGPT is good at, so here's a dozen more examples if you want: https://chatgpt.com/share/67e6d457-5ff4-8002-a5c7-15040f3d22... .
Is "an ouchie" a thing that someone performs or does?