I said "your phrasing sounds like" specifically to make it not personal. Clearly some information was missing but I wasn't sure exactly what. I'll try to phrase that better in the future.

It sounds like the information you need is that cp has a flag to make cloning happen. I think it even became default behavior recently.

Also that the article quote is strictly talking about dedup. That downside does not generalize to the clone/reflink features. They use a much more lightweight method.

This is one of the relevant syscalls: https://man7.org/linux/man-pages/man2/copy_file_range.2.html