The American way would probably be still using the units you listed but still meaning 1024, just to be confusing.
American here. This is actually the proper way. KB is 1024 bytes. MB is 1024 KB. The terms were invented and used like that for decades.
Moving to 'proper metric' where KB is 1000 bytes was a scam invented by storage manufacturers to pretend to have bigger hard drives.
And then inventing the KiB prefixes was a soft-bellied capitulation by Europeans to those storage manufacturers.
Real hackers still use Kilo/Mega/Giga/Tera prefixes while still thinking in powers of 2. If we accept XiB, we admit that the scummy storage vendors have won.
Note: I'll also accept that I'm an idiot American and therefore my opinion is stupid and invalid, but I stand by it.
This was not allowed before. Until just recently, the technology didn't exist to place icons anywhere in the grid. They would automatically smoosh up into orderly rows starting at the top-left with no gaps between icons. Apple is continuing to develop cutting edge innovation, though, and now you will be able to leave entire rows and columns empty, or any specific icon space you choose!