A well fit joint with minimal glue will do two things. First and most importantly, it will be stronger. Secondly and also most importantly it will be lighter. Glue is heavier than balsa. Add all the joints in an airplane together and a plane with tight joints will be significantly lighter. Add other weight saving tactics and you've got real weight savings. Grams here and grams there equals ounces overall I've saved as much as 25% - 30% through the use of light balsa and tight joints.

To quote a wise man, lightness is next to verticalness.

Dave