@dannydb a quick way to remember it is that markers that can't be moved or removed (turf war, leylines) are ht5, blocking.
Markers that can be moved or removed (break the line, symbols) are ht0, concealing.
All strategy markers are impassable.
As for the advantage against shooing. Personally I feel that the ht0 markers impact me more, as I look for range 2" models, to deny intact at the marker.
If the markers were just impassable I'm afraid people would get shot off them quite often, but it also depends very much in the terrain meta. I've found that when I discuss the viability of models with people online, terrain is one of the biggest factors for why our opinions differ.