Please, please, please Miguel, let us (me) know just how practical and useful you find your monopod to be. I have a problem with steadiness, not my hands, but keeping my body still whilst I am photographing. I sway. I have balance issues too. My tripod is too big and heavy for me to carry around, so I don't! Your butterfly shot is excellent.
Here is a quick initial progress report on my impressions of shooting with my particular monopod, which feels quite lightweight (it's aluminum), and super easy to use (I'm referring to the ease of setting it up and adjusting the leg height). Quick note on the "leg locks" - there are traditionally two kinds, those that twist open (and closed) - or those that flip open and shut. My normal (3-legged) tripod has twist locks, but my monopod has the flip kind and they are much much quicker to adjust.
Then there's the head (i.e. how it attaches to the bottom of your camera). My monopod had zero adjustability so for me a decent head was a 'must'. I'm a fan of ball heads (which let you move or adjust your camera framing in multiple ways & axes).
@John King recommends a grip ball head which obviously has many advantages, especially ease of use and adjustability. The downside is they can be pricey, and add a bit of weight to the overall package. In my case, I was able to use a cool and rather ancient small Cullmann ballhead. The good news: it lets me micro-adjust my angles and framing. The bad news: like most ball heads, it requires me to a) loosen the (small well-designed) clamp that secures it - b) adjust the framing & angle - and then c) re-tighten the clamp. It's not that complicated - but it lacks the simplicity of the just-squeeze-adjust grips which John mentions. But I honestly don't mind taking a few seconds to readjust my ballhead as necessary.
Also - and this has to do with how I am used to shooting - normally (in pre-monopod days), using a lightweight telephoto (like my Olympus 75-300) on a lightweight camera (my Olympus E-M5.3), I always shot handheld (which is how I tend to shoot 99 % of my photos anyway). The big problem of handheld with a long telephoto is keeping the image steady. Even with excellent Olympus IBIS, and even using relatively quick shutter speeds, I still tended to get quite a few blurry shots - which I attribute both to my not-perfectly-steady hands - as well as to the difficulty of handholding the equivalent of a 600mm FOV.
So far at least, my monopod shooting experience - is that the camera "feels" much much steadier. Even though my camera + lens is relatively lightweight, now when it's supported by the monopod, it seems like I don't have to work as hard to keep the damn thing steady - and instead, can focus more on what I'm trying to frame and shoot. Which for me is a huge plus. My initial results seem to indicate that, with the extra support of a monopod, more of my shots are steadier and clearer. Here's one more example from a recent shoot in my garden--
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This is the kind of shot which more often than not tended to come out either slightly blurry or slightly out of focus when shooting without a monopod. (For a variety of reasons doubtless, not just my own lack of steadiness or the difficulty of shooting extreme telephoto handheld, but also my focusing issues, and the semi-notorious difficulties of holding a lighter lens as steadily as a heavier one). But with a monopod... the photo is much closer to what I hoped it could be.
Choosing a monopod, I was influenced both by weight considerations (I wanted something light weight, so I picked aluminum), and price (many of the older, borderline ancient Slik monopods not only have a good reputation still but are stupidly affordable, compared to the newer, often pricier ones). Getting a ballhead was a 'must' for me but I was lucky since I already owned a good and relatively lightweight one.
The other big plus is practicality and ease of use. Though it's arguably less stable than my tripod, the monopod is also much easier to 'set up', to carry with me, and lightweight enough to take on longer hikes. So... I'm now a monopod fan! Although, weirdly, having shot handheld forever, I think there's a bit of a mental-adjustment-learning-curve for me, most of which is simply deciding to try a different way of using my camera.
Hope some of this helps.