Officially, short answers in comments are not allowed. I actually do this quite a lot because:
- You can help someone out when you don't have time for a full answer.
- The length of full answers can cause people to over-complicate or suggest extremely risk-adverse approaches.
- A lot of questions are dupes, but it's quite hard to find them using search. I may not want to answer a dupe question, but can stretch to a quick comment.
- Sometimes people respond better to a quick sentence that gives them some phrases to look up, rather than a self-contained answer that spells everything out.
- While I'm prepared to offer general advice appropriate to their situation, fully understanding a question's unique situation feels more like doing consultancy.
This seems to be pretty common as well. Actually, shout out to schroeder who often leaves really helpful comments, especially on questions that can be easily Google'd (and others do too!)
Can we just skip the "don't short answer in comments" rule. Even if it's general SE policy, comment policy seems to be devolved to individual sites.