It probably has TLS 1.2 so yeah easy to hack, especially when with IPV6 it will have its own public IP 
What features does it offer, that it needs internet connectivity? Posting teeth photos? Keeping log of kids brushing their teeth, so a helicopter parent could stay in their couch? I guess my imagination in that case is insufficient. Of course I ask about features that are appealing to the consumer: because from company’s point of view the benefits are clear.
Also, the forum offers attachments. Please use that instead of spreading post content across multiple services. Thanks
Anyone who would buy an "intelligent" toothbrush is lacking something.
Let people decide for themselves, what they want. Somebody will judge you the same way from their own limited perspective.
The problem is not in what one choses individually. It’s in this being a mass effect, that shifts the entire market, in the end limiting individual freedom of choise. It’s like all people voting witht their wallets for “smart TVs,” making it not almost impossible to buy a normal one.

like the BOSCH torque wrench, it will not be long before a ransom is demanded for the act of brushing teeth. 
But look at it from a different perspective. Actors demanding a ransom are doing this illegally and are frowned upon. Companies, who require you to subscribe and effectively only license you devices, are doing the same, but they can do this openly and society thinks it’s normal.

In fact, a electric toothbrush with a motor and nickel battery charging circuit is enough to make teeth smooth.
And so is a plain, non-electric brush.
There never was research electric brush manufacturers have to support their claims. Outside that there is little research on the subject in general, the overall conclusion is there is no
notable benefit, and any observed positive effect seems to be not from their operation, but from people somehow chosing to brush teeth longer with electric brushes.