First, bitcoin is an extremely volatile asset and history shows that the volatility is not only one sided. If bitcoin’s price was almost multiplied by five over the past year, it doesn’t mean that it won’t come down crushing.
The high volatility in bitcoin’s value will therefore inevitably inject a certain volatility in Tesla’s revenue, and decrease the predictability of the company’s performance
Second, buying a Tesla car in exchange of bitcoin is basically betting that the Bitcoin’s price will either stabilise or fall.
No one would bury his or her bitcoins in a car predicting that its price would triple again in the next few years.
Well, the contrary could happen as well, but it’s a casino bet. Unless the price of bitcoin stabilises, either Bitcoin’s price falls drastically and you end up having won a Tesla in lottery, or its price triples and you end up paying your Tesla far too expensive.