This is just the same approach as Coffee Joulies, which is a former Kickstarter project. I have a bunch of these, they work well. No need for a custom mug.
Sometimes the reason for having is in the having, not in the utility. Any geek knows this.
If Apple sold an insulated iMug people would queue up for it. You know this to be true.
they'd also be suing samsung for patent infringement with their damnable galaxy adro-mug