I don’t know how to answer that question. I feel like it’s a given that looking younger, after reaching a certain age in one’s life, in western society, is an advantage and desirable.
If your current weight is between underweight-26 bmi, then my answer would be yes. Scrawny is not pretty or healthy. Of course these numbers are not cast in stone, so get a second opinion from someone you trust.
I think that people should try to be as natural as possible about their eating habits and not eat more or less than they feel a need to simply for the purpose of gaining or losing weight for appearance’s sake. But that is just my opinion.