But other arty pieces are on maps, while the Brit arty is an off map that just happens to be on the map
damage of an on map (not even) with the restriction of an off map.
The worst of both world.
the sight restriction work with normal off map because they are powerful and not affected by range. One strike is normally enough to kill anything caught in its area.
on map firing into FOW (normally) work because of FOW penalty, and relatively low alpha strike.
The british base 25 pounder combined the worst of both type without any real advantages. It's just inferior off map.