There's an epic conflict of interest here with Musk owning most of both companies. And they're in entirely separate fields, there is no plausible synergy here to be gained.
You don't need synergies to justify a merger. They're often used as justification as in paying well above market price. But it has nothing to do with actual justification. You can just have a holding company of businesses
edit: these replies aren't going to age well
literally (adverb)
informal : in effect : virtually
Used in an exaggerated way to emphasize a statement or description that is not literally true or possible.
Ex: I literally died of embarrassment.