I do this all the time manually, but it's not hard or time-consuming. Why would I want this service trying to do it? It takes me maybe 5 minutes to block out the portions of my week that I don't want people to schedule over.

(Of course, they still schedule over it. But they also schedule over real meetings, so I don't think there's some magical way to name a meeting that makes it seem important enough that the meeting locusts won't try and eat more hours than you have in a day.)