That doesn't make it the answer though, just something else that might be beneficial to mention. As an answer it obscures whether the original question had mer

That doesn't make it the answer though, just something else that might be beneficial to mention. As an answer it obscures whether the original question had merit and leaves it unanswered. As something that's included alongside an answer it is superior to an answer alone and to itself alone. I agree whataboutism can be useful in causing people to reassess their perspective on a topic, but when used haphazardly it can obscure more than clarify (and has been used this way extensively in the past for this purpose).