This comes up frequently, and the meta-question is basically a duplicate (see below), but this time let me try to pin down the problem with this type of answer.
If verifying the answer is just as hard as answering the question, the answer-post adds nothing.
Let me elaborate. Literally just yesterday, I came across an answer to a similar question that said also "Yes, this is correct." just like here. No problem for some, it seems.
However, in that other case the account that gave the answer was completely new.
Let us step back. What does that answer actually add? All we really know is that somebody decided to post "Yes, this is correct."
The value of it initially hinges purely on the credibility of the user-account that posted it. Somebody could just as well simply throw it out there hoping for some votes that then, somewhat ironically, validate the answer. I mean, one could even write a bot for this: If tagged proof-verification and body contains "Is this correct?", post answer "Yes, this is correct. Good job, well done."
Granted, if it comes from an account that, like in this case, does have credibility, there is some value to it. The value is in the act of the answer-post being produced, not in the post itself.
However, systematically it is not at all a good idea to allow a format of answers whose value comes only by way of the account to which they are linked. This goes directly against the entire idea of the site that posts are evaluated based on content, etc.
What if meta OP decided to delete their account in the next few months (I hope not, but for the sake of argument)? We'd have an essentially anonymous answer that asserts that something is correct.
What value does this have for somebody that cannot evaluate the veracity of the claim, which crucially includes basically everyone that actually would ask the question?
An answer to such a question should add some actual information and knowledge to the thread. For some ideas what one could include see, e.g., my answer to
How to answer proof-verification questions?
If somebody cannot or does not wish to add such a more detailed answer, but wants to add a quick note they still can comment. Indeed, that leaves the question formally unanswered, but in my opinion that is actually preferable in this case, and I do convert such answers to comments with some frequency.
The same goes for most "yes/no" questions.