let everyone around you know that you are a photography enthusiast

For another,this wristband can also use to stop lens zoom creep. Lens Zoom Creep is the effect gravity can have on your zoom lens under certain circumstances. It is common on the lenses with a lot of elements inside and usually it is the heavier lenses that suffer from it the most. Such as the 18-200/70-200/17-40/100-400, It happens when pointing the camera either upwards or downwards when shooting, when you shooting at slow shutter speeds with the camera on a tripod,the wristband will prevent this efficiently.

If you forgot to bring the diffuser,maybe you can use it to make a diffuser or even use it to hold the gel on the flash.