The numbers are optimistically legit -- it's calculated based purely considering we have demand for all machines at all times. We don't have that right now, but fairly optimistic that people will do it.
That's why we don't recommend purchasing a new machine. Existing machine is no cost for you to run this.
Electricity is one cost, but it will get paid off from every request it receives. Electricity is only deducted when you run an inference. If you have any questions, DM me @gajesh on Twitter.