I have a skyhook. I had it in a cafe for about 6 months. Not one sale! The lack of exchange integration indeed made it hard to trade so as to make a profit - price volatility. It is now sitting in storage. The Project Skyhook team no longer responds & the system is not maintained.
Once, I sent a few hundred worth of btc (at the time!) to the machine in 2015 to top it up. I messed up and sent it to the skyhook company address and not the ATM. No reply and no return of btc.
Hopefully some techy will develop the code and I will have it out in the world again one day. : (