They are for wood joinery. You cut a half-moon slot in the edge of two pieces of wood you want to glue together, and stick a biscuit in the slot (with glue, of course). The biscuit provides additional glue surface and stiffness for a stronger glue joint. I mostly use them for panels, where you are gluing multiple skinny birds together to make one large, flat board (like a table or desk top).
They are for wood joinery. You cut a half-moon slot in the edge of two pieces of wood you want to glue together, and stick a biscuit in the slot (with glue, of course). The biscuit provides additional glue surface and stiffness for a stronger glue joint. I mostly use them for panels, where you are gluing multiple skinny birds together to make one large, flat board (like a table or desk top).