IoT toothbrushes will be able to sense gum disease, cavities and so on via sensors, not to mention analyse your saliva for things like cancer, while also tracking your brushing. There are plenty of IoT use-cases for toothbrushes.
You obviously have not thought deeply on IoT yet. Any purchased object that is always needed, like a toothbrush, will sense when it is close to needing replacement, then self order. Expect to have IoT capabilities on every can, packet, and bag in every supermarket within 10 years. Who likes grocery shopping?
In what type of make-believe reality do you guys live in? 99.9999% of the people in the world are lucky if they have teeth and can barely afford a regular toothbrush let alone an IoT Toothbrush that detects gum disease, analyzes your saliva for cancer, and reorders replacement heads.
Come from Beyond is claiming that Iota only requires a 16KB microprocessor to make txs and broadcast. That kind of hardware is dirt cheap.