they sure are

How did someone hopper loot then...?

by using a dispenser to spit a hopper minecart onto rails

How do you place hopper minecarts then!? I can't place them.

using a dispenser. I don't recommend you experiment with it, you might get in trouble over a misunderstanding

Darn... so much for using hoppers and furnaces (Putting netherrack into furnaces for coal blocks)