Re: Sorry to be a killjoy, bit it's dumb.
The BBC Micro of old cost the equivalent of about £1500 in todays money.
I recall that they were not readily available to most people.
I saw one once, in a magazine.
This little thing is like an Arduino Leonardo with a 5x5 LED grid and some lace holes to make it wearable (with a li-poly battery) If we are to believe the prototype photos are like the intended final product. It seems to be to be very much like an existing device, so it's just an adaptation. It seems to have IO pins too. I don't think that this will be about the device itself, but the bulk of the effort will be in the supporting resource and educational material.