The upvote arrow tooltip reads
This answer is useful
"How to answer" reads
Make sure your answer provides [what is asked] – or a viable alternative. .. Any answer that gets the asker going in the right direction is helpful ...
Then how good is
No [some fluff that is not helping either]
as an answer to questions that invite workarounds? People might not know what others can come up with. I'm sure a lot of people sometimes get surprised by how someone else does the same thing in an unexpected way.
Reasons why I don't like them:
Saying no simply implies
I don't know how to do that.
which is clearly not a helpful response to a question. If a question is left unanswered, it means that those who saw it didn't know what to do.
It might discourage some other answerers from finding workarounds.
As one's reputation increases, the weight of their No also increases.
Samples (and a customary I'm not calling out):
A fun and a bit related question on Math meta: