It takes longer than that. And sometimes, especially with events, you may not have more than a few minutes available at the time you need to resend them to avoid having them idle. Sometimes their timing means it's outside of your normal gaming time. Sometimes you just want to login to send them out and get back to work in real life. Like PVP, not everyone likes it, but many do. So, also like PVP, it's there for those who want it and those who don't want it don't have to use it.