Any bipe I ever built had interplane struts that were just for looks.
If I went to the trouble of fastening them securely to the wings, the slightest
crash would bust the struts and gouge out chunks of both wings.
For a while I left the struts out, but that looked really clueless.
So I fashioned struts from balsa with thin wires at the ends which plug into
little pieces of tubing glued to the wing.
Flimsy and useless, but they look right.