I'd guess few of the hunters reading this piece own a monocular and many have never even tried one. I own two of them and think they are great little optical devices. For starters, they're by definition, half the size and weight of a binocular. So, whenever weight and size are an issue, the lowly monocular is worth serious consideration. Additionally, a monocular is always more rugged than a binocular. This is because no merging of two separate images is required to keep them functional. All the binoculars I've had go bad, have fallen victim to a misalignment of those two images. Lastly, since monoculars are essentially half of a binocular, they are less than half the price of an equivalent quality "bi" optic.
What's not to like? Monoculars do have some shortcomings, including being more difficult to hold steady, but this is largely because people tend to use them with one hand. If you use a second hand for support and stay at or below 8X in magnification the problem largely disappears. Another issue with monoculars is the lack of depth perception they provide. Spotting scopes don't have it either, so it's not a big deal to me.
The two monoculars I own have semi-permanent homes in my vehicles. It's incredibly handy to always have an optic within reach when on the road. I use them regularly to do things like check fields for game, identify unknown objects, read distant signs or look ahead to see why traffic is backed up for two miles on the freeway. I used to carry binoculars in my vehicles, but quality binoculars cost a lot and I don't like leaving bait for thieves in my truck. Cheap binoculars never survived because I kept them stuffed into a door pocket, and vehicle doors do a lot of slamming. I switched to monoculars and it's been a successful experiment.
Like most vehicle doors these days, mine have molded pockets for drink containers and a Vortex Solo 8X36 monocular in its protective case, fits those pockets perfectly. The 8X36 is a great balance of magnification and brightness, with the Vortex version featuring an integral utility clip, fully multi-coated optics, fog and shock proofing, as well as their lifetime warranty. With a retail price of about $100 it doesn't hurt to put one in each vehicle.
Additionally, if I'm just taking my camera for a walk, or want to travel light for any reason, I'll often put a monocular on my belt for those quick looks at distant objects that pop up. The key to a monocular's utility is understanding the design's strengths and limitations. Work within those and these little devices have a niche which products like the Vortex Solo fill perfectly. Sometimes "mono" is a better choice than "bi."