This guy is only playing with you and the markets. It's all fun for him, he's just trolling.
He was playing with real intention of making money.
This tweet does not only give growth to DOGE but it has also affected other altcoins as Elon is the new hype of the market now.
We don't know if its over or there will be tweet to come soon, but he is really the hero for bullish people since his tweet can move the market resulting into millions or billions in price movement in overall.
when the price of Dogecoin has increased in price not only will Elon Musk make a profit, but everyone who holds Dogecoin has made a lot of profit and did not think that the price of Doge could be this expensive, the cryptocurrency price movement will be very good because when there are influential people coming in and supporting full force as happened to Dogecoin with Elon Musk.