You may joke about headsets but I have been using my own noise cancelling headset for years and wear it for nearly all the time I am in the seat. It allows me to turn the volume significantly lower, than if I was using those terrible Telex headsets on the 777. The lower noise levels also help me feel less tired too, so I can appreciate why some may ask about this.
I have also lost count of the number of times I have had to prompt my monitoring colleague about missed calls, when they were using the speaker instead of the headset.