Option 1: Autopilot isn't where Tesla wants it, and they are trying hard to get it up to snuff, since so much has been made about how far ahead of everyone else Tesla is.

Option 2: In the opinion of a Tesla analyst who works for a bank that underwrote Tesla capital raises, it's a strategic move because the Autopilot is so awesome that it will eat away at Model S sales, though the mechanism by which that happens is unclear. And of course, Elon Musk is known for keeping things close to the chest.

I mean, it could be option 2, but I know where I'd put my money.

That makes sense, seems they want to avoid (stem?) people not buying the model S and waiting for the cheaper model 3.