Yeah, I agree with you cloud mining or other mining form using website is not really profiting because there are already huge mining pools using powerful computers to solve the calculations being sent in every transactions especially for bitcoins. GPU or computers that has been use in mining are not even profitable anymore again due to the reason of the large mining pools that can easily create blocks for mining to confirm bitcoin transaction. So, decentralized mining now would not be advisable and just a waste of money unless you wanted to fund mining like having a huge mining pool business too for bitcoin and other altcoins in the market.