I gave about an hour ago a one-line answer to this question, stating that a finitely generated algebra over a field is noetherian, and that a previous answer (by me, among others) had shown that the algebra was not noetherian.
My answer was removed and replaced by a comment, under which stood the (unsigned) explanation that the answer was trivial and hence converted to a comment.
That the answer was trivial is relative: it tautologically wasn't for the OP but it is certainly also true that anyone with a moderate command of commutative algebra will find it obvious.
Anyway, my rationale is to keep answers and comments disjoint: if someone asked how much is $2+2$, I would answer $4$ in an answer box and not in a comment. Call me literal-minded if you wish...
Shouldn't answerers be asked to delete their answer, instead of being forced to do so?
Edit
I thought the conversion to a comment had been done by a moderator, but Martin's comment below and Mad Scientist's answer explain that it is actually an automated process.
I apologize to all, but especially to the moderators, for this misunderstanding on my part.