Planning on making an Electroneum Mining farm with crappy cellphones

So I'm thinking of buying a bunch of cheapo phones for a few bucks and using them to mine for Electroneum. I'm currently using my Note 8 to mine in the background. It's able to mine the ~10 ETN needed to pay out every 2-3 days. Which isn't a great turnaround since each coin is currently worth around $0.01 right now but averaging that out it's about 100 ETN a month. But I figure that if I buy a bunch of Cheapo smart phones (For about $5 each) and have them mine at work, Let's say about 10 phones and have them mine as a referral under me I could double dip on earnings and get my money back in about 8 or so months, which is about the time any miner would take to to be paid for. Plus I would put the phones at work so I will have $0 cost and just collect. And if ETN goes up in value that would just mean more profit.
Any advice?