That´s right most people don´t calculate well their cloud mining contracts profit and roi. Hash24 is very expensive compared to hashflare and genesis mining, maybe because they rent their mining power from bitfury? Anyway I don´t see any reason to prefer hasing24 over other alternatives. Also you must not take into account the possible rise in bitcoin price to calculate your mining contract profitability, as you can take the same profit from just holding your coins. I made and article about genesis mining roi and break even point and it takes more or less 10 months to get your initial investment back, with hashing24 should be significantly more. cheers.