A physical Black Pro Mist filter is always going to diffuse light better than an ADC'd emulation working on quantized data. It's noticeable if you look.
Of course, if you got a filter that does exactly what you want and you are going to use it a lot, there is nothing wrong with that and you may get more precise effects than post processing. But the post is about lenses, which are bulky and more expensive than filters. To me it makes more sense to invest in 3 clean lenses (travel, telephoto and compact zoom) than ones with built in distortions that I may not want for every photo. If someone is sufficiently wealthy, athletic and dedicated to carry a suitcase for 10 lenses everywhere, hats off to them I guess. Even filters are like $80?