I use them where they won't be seen in the final assembly, and mostly so I don't have to use clamps when gluing and assembling my projects. This lets me continue assembling in large sections, or do the complete assembly without the need to wait for the glue to dry before removing clamps so I can continue with the glue-up of the next stage if the assembly. I don't depend on them for full joint strength, letting the glue do the work of holding the project together. Because I hate their look in places where they will be seen. This sometimes requires using clamps, and when this happens I then have to wait for the glue to dry before I can continue. Still, they let me work faster, and this is my main reason for using them.
Charley