They definitely have their place......too bad they don't make 'em anymore. I should never have sold it when I bought my first quad, there have been many times I wished I still had it.
I used to have an '84 Honda Big Red, 200 cc, shaft drive, hi-low trans. with reverse, it was the "cadillac" of ATC's in those days, $2500 new, and by far the best of the 3-wheelers that was ever made. Used it for 14 years, ran like a clock, never let me down, and cost me nothing except gas and oil, other than one bad day (see below)
Lost count of the number of moose it pulled out of the bush and swamps. Many times, while everyone else was wallowing around in the gumbo winching and cussing their quads out of mud-holes, I would just motor around them high and dry, with a big smile. Could skirt around the edges of marshes, meadows, swamps, and lakes, where quads would never dream of going. If it got stuck, which was very rarely, just got off, picked it up, and moved on. Didn't need trails thru the bush, it was so maneuverable you could wiggle it anywhere. While everyone else was guzzling 2-3 gallons of fuel, I'd only burn about 4 liters in a day. A jerry can of fuel was plenty for a week long trip. A breeze to load and off-load.......no ramps, ditches, ropes, pulleys, winches
On the down side, it could bite you bad.....unstable on side hills, dangerous coming down steep slopes, could get away on you at high speed down a road, and I had a real bad day with it flipping backwards going up a steep hill......closest I've ever come to death. 24 years later my back still reminds me of it. The trykes don't pack as much as a quad, nor are they as comfortable, that's for sure..........they sure were fun though.