Yes No - Maybe So
I am not bias to polarizing filters and over the years did without the need to use them, but yet I have a few in my bag, why?. Once you understand when, how and how much - it becomes a matter of the situation that best serves the intended purpose. So don't be afraid to use them in your work - they definitely have their place in any landscapers bag for sure.
I know some say they enjoy the scene as the eye sees it - all the while wearing polarizing sun glasses: the scene can appear differently to different people. This is a fact, especially for certain use cases such as age, eye wear, lasik. Ultimately though, the photos are normally viewed on a computer screen or shared with others using social media. Monitors are not standardized, what appears pleasant to you may appear washed out on someone else monitor. Normal is subjective.
Using the Polarizing Filter: The modern polarizing filter offers the ability to dial in the "right" amount of "filter" and this is were I say, moderation might be the best policy. You do not necessarily need to dial in 100% polarization every time, and some of us over do it. Not every shot needs to be super saturated with super dark blue skys - this is not necessary. Some polarizing effects are normally more pleasing and get the job done without always going for the max. So, when folks say it is not needed, think not needed at 100%, unless of course that is what you are going for, then go for it. My point is they do and have a place in photography.
The argument doing it in post: Screw that, I rather have a filtered image rather than try to apply some software setting to emulate the effect, nothing beats a good filter on lens.
Cost: Yes, you have some $ outlay, buy one for your favorite outdoor lens and go for it. + step down adapters are an option in some situations, be careful of the super wide lens "vignetting". My experience tells me those super wide lens often require little polarizing.
When I don't use a Polarizing Filter: I don't like using polarizing filter with my tree landscape images - shooting up, it over saturates the image.
Conclusion: Nothing wrong with trying a polarizing filter and if you find it not useful, drop it on ebay.