If a robot owns Bitcoins then people might start attacking them to steal their Bitcoins. Exchanges get hacked despite their efforts to protect themselves, and if robots have Bitcoins they are likely to get both physically attacked and hacked. If your washing machine robot owns Bitcoins in the future then you might return home to find the burglars have dismantled and hacked it for those Bitcoins.
Everything will be created with its security, so we can avoid this risks. Maybe that robot be equipped with a tool to its self defense, like weapon. Actually the inventors surely have thought all risks that can be happened to their creations.