When I looked into it last year, I thought it was definitely interesting.  The giant problem seemed to be getting ahold of the hardware.  It seemed like dealing with the hardware manufacturers was a borderline scam.  The hardware used has to be pre-approved, and the only pre-approved hardware was basically a router based on a $35 raspberry pi compute module.  They would then mark it up hundreds of dollars.  You would then have to pre-order and wait months while hoping you actually got it.  Not sure if Helium is an outright scam or something they truly want to see happen...