I bought a ETH contract last year from Genesis Mining and I quickly calculated that I would get about half of what I could have if I bought it out right. After a year I found out that I was right I paid about $37 in BTC last year when ETH was about $10 so I could have bought 3.5 ETH but instead I got the mining contract and made a little over 1.6 ETH. The only way to make more than just purchasing the coins is to get a bunch of people to sign up under your affiliate program and I feel like that is what lots of these You Tube channels do.