When bikers find out about sidecars, the emphasis is often on carrying additional passengers (children, dogs, etc.) or driving down the street and having people wave at you.
After a few years of hacking on the street, I discovered the fun of drifting around unpaved roads. Frankly, I'm not comfortable trying to ride a bike through technical situations--such as deep loose gravel. But on a rig I'm comfortable doing stuff I wouldn't try on a two wheeler.
So, if you're thinking of a hack only as a street rider, consider that there are lots of roads that aren't paved, capable of taking you to spectacular scenery, and most of all--fun.