People knew more about macros before bio-pellets and GFO... it was all that we had along with water changes to keep the nutrients low. Like most of the old-timers, they don't need any help and don't like to argue with the experts that have had a biocube for three months and know it all, so they rarely post.
Chaeto can be quite effective, but you need to use it in conjunction with water changes. It will use up all of the iron and stop growing, especially when it gets big. Water changes will replenish the iron and other trace elements. You can dose iron, too. You also need to prune it back and keep the ball loose so that it keeps growing.
Most people just never export it from their tank. They keep it in there, then it dies back and lets the nutrients back in.
When I have seen it not work well, the fuge was too small, people never changed water and they never trimmed their chaeto. You cannot just ignore it... it requires work too.