When I began learning Ruby, this was one of the first exercises in the first chapter of the book I was using. They had you write 3.minutes, 3.hours, 3.seconds, etc. I can find the book if needed. It may be true that strong ruby developers likely will not do this, but then why teach bad practices to beginners?
I don't know about expecting other languages to behave like [that] too, but the Ruby community certainly does a lot of monkey patching. When I was developing in Ruby I saw this often and it annoyed me a bit.