This is a very interesting theory, and I would lean towards it. I do not believe that it is just a mere coincidence that the Chinese government made their decisions to ban all cryptos just before they celebrate one the most important festivals in the country. It looks definitely as a ploy for individuals to become more liquid (that is change their bitcoins into cash) so that the cash would be spent, used or traded heavily during this season of festivities for them. They more cash circulates within the season the more growth you see in the economy. Otherwise people would have held their bitcoin and other alt-cryptos, anticipating more growth for future gain. You may even have the situation where instead of people investing in the festival period, you see more investment in crypto-currencies which could damage Chinese economy. This seems like a major move for the Chinese government within this period.