The monopod idea is a strange animal.
I have never bought one, even though the idea has crossed my mind many, many times. The problem is, it isn't really holding anything steady in any single direction except downwards, and only partially that, at the best of times. If you consider your camera attached to a position at the centre of a large ball that is only prevented from falling vertically downwards, you will have the concept. Anything that the ball can do, in terms of rotation, your camera is going to do as well. It can drift off to the side, to the front, anywhere at all except vertically down.
There's a better proposition I've tried from time to time.
Apart from the doctor's best friend, the Gitzo, I also have a relatively light but firm Slik tripod with fitted tilt/rotate head. The trick is this: extend two legs only, and have them at the left and right of the direction you want to shoot. That limits your accidental drift to up or down, far easier to control and also very easy to discern if it is happening. Why, you might ask, as did my wife, not use all three legs as you have carted them with you anyway? The simple answer is: speed. Using a tripod as a tripod takes time and is pretty fixed; using two legs is amazingly versatile in use, just as long as you don't foget and let go! But you wouldn't do that, would you?
Try it before you doubt it; this is something you can safely do at home.
Rob C
