Yea but when hornwort does die, which it will after a period of neglect, it will leave hundreds or thousands of little needles all over your tank that will decompose and cause water problems, also they love to get clogged in the filter! Or at least that's my experience with them.
java fern is great stuff you may not be able to get it to flourish under bad conditions but the "root ball" will stay intact and can regenerate the leaves when you apply good light and some plant supplements! ~ my experience also.same with the moss, but not a root ball, it's cool anyhow. It does explode overnight with good conditions, I have way more than I know what to do with.