I like these types of filters for some games but usually disable them, especially for games with a very intentionally gritty look. Sometimes a decent looking fake scanline filter is a good addition too, regardless of whether you smooth or not. As you said it's just personal preference. With that being said, I don't think they're going to accelerate them any time soon. For one thing that's up to the filter plugin author to implement via shader code. I can't see it really being necessary though, I mean a multithreaded xBRZ shouldn't be THAT heavy.Yeah, for some of static art. But there is also a whole bloody lot of old 320x200 to 640x480 games that start to look totally great in modern resolutions after applying xBRZ.
I pushed DOSBox xBRZ patch to DOSBox-X a good while ago, so you can try it and easily feel the difference yourself.
Of course I'm not implying you will or have to like it, it's just a matter of taste in the end