I will answer this with the quote from this article:
"A properly designed token sale doesn’t promise ‘investment returns’, ‘dividends’ or ‘profits’. Instead, it focuses on selling a digital asset that will have a clear use case in a decentralized application, as a means of both incentivizing development and solving the chicken-and-egg problem for the network. A properly designed token actually serves a purpose: it is required in order to participate in the network, rather than just being a funding mechanism."