I think it's "money never sleeps", and that's because there's always a market open somewhere since we're not all in the same time zone. Your local stock market might be closed, but people do trade globally. Speaking of this particular phrase, if you haven't seen Wall Street 2: Money Never Sleeps, check it out. It's a pretty good picture.
The context of the phrase money never sleeps is pertaining directly to the function of cryptocurrency or any other currency in the market. It is quite an obvious thing to know that when we have a currency or a form of something that we could used upon on transaction, investment or trading there will be a higher chance for it to experience development and changes on its system for it to be more functional for people and to have a better use in the future. And when we say never sleep, it also means that never stop developing or having and progressive changes in a benefit of the many.