Dust War.

These seem to be humidifiers. If that's what you mean, they work at reducing static and improve air quality.  Ultrasonic units need distilled water. Do you mean purifiers? To filter dust? If so, yes, we have one in most rooms and they work as long as you replace the filters when needed.

@noromance 

yes - air purifiers from dust (fan + drum / filter + water tank) ... how much is it advisable?
... if now cleaning electronics from dust (vacuum cleaner) once a week, then how will the interval change approximately if you use an air washer? ...

humidification mode is probably dangerous for paper speakers - you need to be careful.

We use Hathaspace and Fellows and find them very good for clean air quality. I can't specifically say that I've noticed less dust around the stereo but the filters catch a lot so the dust is definitely being caught. 

Dust War??

That's DEA terms on a Mexican boarder.