We also use these for Double Bar Lines and Repeat Signs (with the Dots we supply as a card of 4 Dots).
They can be cut to size to be used as beams, for instance with Crotchets to make Beamed Quavers. And cut to make Ledger Lines.
We also use them for Slurs and Ties (they're not ideal, as they're straight, but they work!)
Crescendo and Diminuendo signs can be made. And tails for notes if you've run out!
All in all, a multi-functional tool!