I will personally agree with the poster in some circumstances, like it depends on the coin or token you are holding, they are some coins or tokens that doesn't have enough liquidity to support or make trading that coin or token easy, you can buy them, but selling them some times takes days cus there aren't a lot of buyers around willing to buy your selling price, and again, the individual have to know how to trade, if not, he's gonna end losing he's or her stash instead of increasing it.