Subpoenas are orders, but they're not necessarily court-issued. Warrants, on the other hand, are court-issued -- the police can't issue warrants on their own in the US.

A warrant for a things isn't an order to the owner of that thing. It's an order to (and peemission for) officers to go and seize the thing.

You get shown the warrant to prove that they have permission, not to order you to comply.

Yes, I'm aware -- my other comment says that.

I realize this comment is a little ambiguous: the order in the warrant case is an order by the court to the court's officers to perform an arrest, seizure, etc. It's not an order for you (the subject of the warrant) to comply.