It works without a subscription. The subscription is an extra on top of the bed. It's main value is a temperature thermostat with 2 separated water cooling layers, which can be a godsend for some.
"But, you see, what we're really trying to do here is redefine the mattress industry, from providing a passive product into more of a compelling interactive sleep experience..."
There is no justification for why a bed mattress should require a subscription.