You missed the point. It's not the part that uses standard interfaces -- all these SSDs comply with those standards -- it's the part not specified by standards

You missed the point. It's not the part that uses standard interfaces -- all these SSDs comply with those standards -- it's the part not specified by standards that matters. For example, we know that some drives produce more heat than others, or are faster/slower than others, and sometimes these two are tradeoffs. For a small handheld device like Deck, it's important to choose a drive that fits the form factor.