But surely 60B could buy you something better if you want to spend money on AI. The number seems completely arbitrary, would Cursor say no to 40B? I really don’t see Cursor as bringing them anything of actual value, it’s more of a bragging thing, but I can be very wrong.

Couple things. First, it was a all-stock deal, not cash, so it's closer to a merger than anything. Second, this deal was determined months ago, most likely at a equity stake defined then. That could mean that a 30B deal 3 months ago is now worth 60B.