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.
He is playing new people in crypto, as what I observed since Elon started to post tweets about bitcoin and DOGE the number of people who have an interest in crypto increases dramatically, it is expected because he is well known, I am still waiting for his next tweet, and still thinking how long will this hype run and how long he will promote crypto?His tweet can hype any coin in an instant but the number of his holdings can make this market crash as well.