He said it fit. He never said the OS mounted it; which it wouldn't given that it has neither a data nor a power connection.
off-topic but you actually can cut your M.2 SSD so that it fits in a WWAN slot for example (source: guide from r/thinkpad)
Yeah...I was going to say if the one on the image had been broken on the other side maybe it could still work. Not in this case tough.
This is a great way to divide a larger hard drive (say 1 TB) into two smaller (500 GB) drives.
Ahh, yes. Physical partitioning
The only thing better than logical partitioning