It just provoked your grumpy head WM
For what it's worth Aggers, I don't think it's necessarily for people who have a lot of time on their hands, some of the busiest people I know use it (chefs running their own restaurants certainly don't have any spare time!).
But that I think is part of the appeal for them, it takes but a minute to communicate.
Several of the restaurants I've seen will put a note on if they have a late cancellation for instance, telling people they can have a special deal if they have the table. There would be no other way they could do that, and a lost table is a lot of money
Just one example, but I'm sure there are many more.