Do many owners live in their garage to maximize house space?

[Roger Simons]

In many areas its risky to rent the garage as its technically illegal and the renter can rat you out anytime. Especially after you've evicted them!  There's also the danger of the tenant doing things you're not aware of because they're far more isolated and have more privacy.  So renting out the garage is usually not optimum. 
But....what if the owner lived there?  They will have more privacy.  and more room as most 2 car garages are actually quite spacious, much larger than almost any bedroom.  Plus there's the possibility of putting in a 2nd floor for a storage/sleeping area/home office area up there.  Its OK if you can't stand up there as you're sitting or sleeping up there.  
The downside of this is you are less connected to the main property.  This might be good for an owner with a young family who needs privacy from others and who wouldn't consider house hacking because of this.