My take: this was calculated.

Notice an opportunity for easy money and get into Bitcoin under the pretense of selling cars for it, then pull out "temporarily" citing environmental reasons. They are now in a comfortable position to hold onto it for how long they might want to, without getting too many questions why a car maker is speculating with crypto coins. If they might need cash (or have to pretty up the quarterly results) one day, cash out some. In the meantime, post doge memes to keep crypto in people's minds.

Profit.