The Costco one is "installed". I can't tell if it's insulated, but it looks like it -- and that along with properly sealed doors/windows (like you'd have in your house), finished interior walls, electrical/lights (?) are a big difference from what you get with a $2000 shed intended for storing your lawnmower.
Another good distinction is Dwellito says "delivered to your front door". I don't know about you, but for me that would be.. quite inconvenient. Getting an assembled 10x10 (? not sure exterior size) shed into my backyard would involve either disassembling a large part of a shared fence (which is 50% my neighbour's), or using a fairly large crane to lift it completely over the house.
Another good distinction is Dwellito says "delivered to your front door". I don't know about you, but for me that would be.. quite inconvenient. Getting an assembled 10x10 (? not sure exterior size) shed into my backyard would involve either disassembling a large part of a shared fence (which is 50% my neighbour's), or using a fairly large crane to lift it completely over the house.