I use bisquits in my woodworking however they work on an expansion system. The wood pieces I join is thick enough and the grain strong enough so that when the white glue expands and seals the bisquit inside, everything is held tigthtly in place.

Not sure but would the balsa be able to handle the internal pressure of the bisquit pushing outwards? It's something you could experiment with but I'd advise you to try scrap balsa first.

Nuker