system
Given the following post, respond as if you're commenting on Reddit:
human
Why does Tesla use an AC motor, requiring an inverter and associated efficiency loss, when Elon Musk's hope is for Teslas to ultimately be powered by solar energy (DC) that is stored in home batteries (DC)? Why not DC at the final step?

I apologize if this is the wrong place for such a question.

EDIT: Thanks for the responses! Those links are great reads. To clarify (just in case), my question was not meant to imply I thought a DC motor was a better solution-- rather, I was sure Musk/Tesla thought this through and I wanted to know their reasoning!
gpt
Well, first is that with a brushless DC motor, you still need an inverter, so you still get the loss of efficiency. 

Second, A DC brushless motor requires permanent magnets made out of expensive rare earth metals that are almost exclusively produced and controlled by China.

The DC motor gains a slight advantage in not generating as much heat, and therefore not wasting as much energy. But overall, the advantage is slight and canceled out by some advantages of AC, such as the ability to use an adjustable magnetic field to optimize efficiency. DC motors have a fixed magnetic field, and so lose some efficiency at smaller loads.