is this a good practice for handling horizontal scrolling in desktops?
Certainly not; to see why all you have to do is shrink your browser window until you get a vertical scroll bar...on that page you cannot vertically scroll, ever. They've ruined the ability to scroll normally just to save you from pressing the arrow keys, using a tilt-wheel mouse, using autoscroll or clicking and dragging the horizontal bar (people forget there are actually a variety of ways to horizontally scroll).
This is one of those cases where it makes sense to stick to convention; even though horizontal scrolling on desktop is rare (and should be), odds are your site isn't the first horizontal scroller the user has seen. They're going to expect horizontal scrolling to work just like it does on other sites (and they're certainly going to expect vertical scrolling to work as it does on other sites). Tiltwheel mice are becoming increasingly common, and the trusty horizontal scrollbar, though loathed so much by designers, does it's job well enough.
Now there is a time and place for fancy scroll effects where vertical scrolling results in paralax scrolling, slideshow effects or other unusual scrolling methods...but those cases are rare, and are part of specialty interfaces like showcases or slideshows, not a normal interface where a more traditional method of scrolling would be preferred.