In the right conditions a CPL will give you much better results with punchier colours and better control of reflections, *BUT* you need to set the CPL rotation before you take off as you obviously can't adjust in flight.
For real estate that's probably not a major problem as you'll know the shot you want up front and the angle you'll be shooting from, so can set the CPL accordingly on the ground. Even so, if you want multiple views of the property, you'll need to land and adjust for any major change of angle to the sun for the best results. If your properties often have pools and/or a lot of foliage, a CPL is also going to give much more appealing shots for prospective buyers.
For mapping/surveying, unless you need to see through reflections on water (which does require a CPL) who cares? It's more about capturing the detail than the composition and colour tone the images, right?
General purpose landscape is more tricky, and it depends on how you approach a given scene. If you like to just fly around and grab shots that appeal then I suspect you'll find a CPL to be an exercise in frustration as it's going to be set sub-optimally far more often than not. In that case, you'll probably be better of defaulting to not having one fitted and maybe having one available in your bag just in case you happen on a scene that would really benefit from using one - then hope you've got enough time and battery to RTH, fit the CPL and get back to take the shot before the moment passes.
If you consider your shots and angles before you take off and don't mind making multiple shorter flights, then a CPL can deliver much better shots and can be worth perserving with. If in doubt, I do a recce without one first, get some shots in the bag, then go back with a CPL as often as necessary for any money shots - again, hopefully before the moment passes.