I used to use one myself a few years ago.
For longer distances they do need to be steady and on a tripod. You also need a fixed reference point. They do not work targetting a leave or rush, but do on a tree trunk or target board.
There is a range limit on building site style laser finders, mine was only good to 120metres.
They work as well outside as inside , not sure how far though as that would depend on the lazer unit , I know mines ok to 40M ,
Not used it for fishing though as I very rarely use wraps .