The design is not just functional, it also indicates origin - like a trademark. They aren't copying Apple for the design, but because it is known and valuable

The design is not just functional, it also indicates origin - like a trademark. They aren't copying Apple for the design, but because it is known and valuable in the market. It's like making fake Coke, in a fake Coke can. i.e. it's a marketing strategy, not a design strategy, to "look like an iPad mini".