I know some people have busy lives and back-to-back meetings. I'm not one of them. I'm having trouble understanding why they need someone to do their scheduli

I know some people have busy lives and back-to-back meetings. I'm not one of them. I'm having trouble understanding why they need someone to do their scheduling for them. Shared electronic calendar software has been around for a while now, and there's only so many hours in the day... What am I missing that means you can't personally schedule your own time with a customer or supplier ? Isn't it just a case of opening your calendar app and finding a mutually agreeable half hour in there somewhere ?