Moss can make an aquarium look very nice,but it can be hard work tweaking it and nudging along its propagation,basically a double edged sword.Most videos showing moss depict a beautiful tight knit carpet on wood or rock.Apart from the odd video where it genuinely has been left to spread over years,I wouldn’t want to know what money was spent to getting it looking so good in an instant.
A shortcut to creating a nice tight carpet of moss is to purchase Marino moss balls and basically flatten them out and then attach to the wood or rock.An advantage of this method is less cleaning,as moss balls are already like hair balls ?.don’t forget moss sinks too,so when cutting Java or any other long thronged moss,it can be spread everywhere unless utilising a siphon to quickly gather the cuttings,meaning it can get in the filter and into nooks and crannies where it will grow if left unchecked.
One last negative,once moss is in the tank,it’s in,be prepared to empty the tank if you ever get bored and want rid of it.one tiny bit left will keep growing.
These are only the negatives if you aren’t prepared to put in the work,moss balls take most of the work out of it,and giving them a light squeeze now and then is all they need.However they can lower pH,but also help with keeping a steady pH.It’s all swings and roundabouts.
The upside with moss is that it can look stunning when green,lush and tight and your eyes will get drawn to it,regardless of how good the fish look.
All in my humble opinion.