I was thinking about the options I had to upgrade my storage when I had an idea.
Some kind of an adapter to plug an SD card directly into a SATA port on a motherboard, in a way that there is absolutely no cables involved. The adapter would look exactly the same as the end of a SATA data cable, but instead of a SATA cable coming out of it, there would be a port to plug in an SD card. And since there's no moving parts, in theory it would be as fast as an SSD. And with a big enough SD card, you could put an OS on it and use it as your primary boot drive. Would that work?
In theory, it should work if there is such cable available but it won't be as fast as SSD.
Another issue is that the cable must come with the own controller coz unlike SSD, SD cards don't have any controller.
For SD cards, they have different grades with different speeds so it play a part as well.