Contraptions that are single-purpose and do their job well are defensible, IMHO, yet I still dislike the space and specialized cleaning requirements of devices like this.
The rice cooker and convection/toaster oven have been the two most universally useful appliances in our kitchen, and they are both still operational after an average of 15 years in service. Other gadgets have come and gone, and they remain. They have even outlasted four microwave ovens, three slow-cookers, and one full-sized range-top oven.
A rice cooker is useful enough in every home kitchen that I consider it a dire omission that they didn't even get a mention in the article. Ours can cook a dozen eggs in 15 minutes, most of that time can be spent doing something else, and there's no boiling water to pour out.