Personal story: Some of my relatives in Thailand play the piano or electronic keyboard as a hobby. Almost all their "sheet" music score books are printed in this notation, but some of my western friends didn't realize it was music at first until they saw the lyrics.<p>Later on, I learned that country music in the US uses a somewhat similar "Nashville System" [1], but I believe that system doesn't let you span multiple octaves the way this system does.<p>[1] <a href="https://en.wikipedia.org/wiki/Nashville_Number_System" rel="nofollow">https://en.wikipedia.org/wiki/Nashville_Number_System</a>