People paying attention to Elon's tweets [1] [2] saw this coming from a mile away. It'll be interesting to see if and when other big companies follow suit. In my opinion it's inevitable companies will start diversifying by a bit of exposure to Bitcoin but let's see how soon that will be.
E.g. it's still not the ideal, final solution - but Tesla seemingly aligning to being on the side of the "army of HODLers" makes business sense; you don't want that army that's financially incentivized via the MLM/pyramid scheme that it is to start rallying against you and your products/services.
I think the tell that it was definitely happening was when he went to visit Larry Ellison in person in Hawaii right after Christmas. What could have possibly needed the approval or advice of a member of the board and was too important or sensitive to discuss over the phone.
Actually in the SEC filing they state that they already changed their financial policy to be able to buy alternative assets. It's interesting that the media didn't pick it up, as MSTR did the same.thing first.
Not an expert, but as an anecdote: every company that I have worked for have had their stated purpose as "Doing X and Y, and also investing in stocks/bonds/whatever".
[1] - https://www.reuters.com/article/us-tesla-cryptocurrency/tesl...
[2] - https://www.cnbc.com/2021/01/29/bitcoin-spikes-20percent-aft...