It's the absolute best solution when fitting to an existing garage with limited headroom. I have a garage that has a front opening of 189cm. Already too low for one of our cars. There's only an additional 8cm of free-board at the ceiling inside the threshold. The best ceiling mount door clearance we have found puts the door at 178 on the ceiling. I'm 183cm tall... that just doesn't work. Side opening absolutely had a market. And the benefit of being able to open it for say, only a meter provides the benefit of being able to maintain front access without the door being fully open as it would on a ceiling mount.
Doesn't seem practical for multiple reasons. (1) takes up an entire wall usually used to build shelving and storage. (2) door covers window which lets in natural light. (3) in many cases, door may cover side entrance/exit door. I'll stick with my current, ceiling screw drive Genie garage door opener.
Perfect for different applications though, gives extra roof space if someone has a hoist, doesn't cover the garage lights when open (as panel doors do), the panels can have transparent section for allowing light in and they can be aligned with garage windows when door is open, as for shelving you'd just need to place it 6 inches off the wall.. not bad I think.