What you're seeing in the image above is an overhead pistol squat while balancing on a kettlebell. This is a fucking ridiculously difficult exercise that requires an absurd level of proprioception, stability, mobility and every other quality that makes an athlete amazing. This athlete is displaying an astounding level of athleticism, but I don't consider this a training exercise. Here's why.
A training exercise is an exercise that you can do consistently, in a "controlled" environment (any environment involving your body and dynamic movements is inherently turbulent) that you can consistently improve upon and progressively overload in order to reap more benefits for your desired outcome.
Training exercises are uncomfortable and tedious and arduous and only meatheads find them "fun". But they make you better for when you want to actually display your ability. If you're not careful, though, training exercises can become displays in and of themselves. If you take a simple exercise like a deadlift or a box jump and start performing it exclusively to your maximum capability, then you've started to showcase your ability rather than train it.
People fall into this trap all the time; I know I have. Putting on a display is fun! Rather than taking the time to load an exercise incrementally and get better at it, I spent several months where I would just go max out on the lift once a week (snatch and deadlift). I increased the weights on both exercises, but it wasn't that I got better at them, it's that I took enough attempts that the percentages were on my side. If I tried snatching 200 pounds enough times, I was bound to get it eventually.
Kelsi trained incrementally for her marathon and displayed her ability when the time was right. Going to the gym every day and maxing out your clean, bench and 40-yard dash isn't going to do much more than crush your CNS and leave you flaccid and weak.
While almost any exercise can be turned from a training exercise into a display, there are some (generally variations) that become displays inherently because so few people are legitimately able to do them. The DB Snatch is an exercise that I think carries a ton of value, but is better served as a display of power or a conditioning exercise rather than a legitimate training tool. The nuances of the exercise are so minimal that it's really just a "here you go, have at it" kind of exercise. I also don't think that being able to snatch a 150 pound dumbbell has any impact on your barbell snatch, but you also can't snatch a 150-pound dumbbell unless you're a strong fucker already.
Many core exercises also become so difficult that they aren't exactly trainable. Ross Enamait is a strength coach in CT and is one of the most legit savages in the industry. However, just a look at some of his core exercises let's you know that for 99% of the population this is a party trick rather than a training exercise you can do consistently over time.
There is nothing wrong with displaying your ability from time to time; that's why we train in the first place, right? But you need to make sure that you're training is appropriate to get increase your ability to display safely and sustainably.
I hope this made sense to everyone! Have a great day, and go lift some heavy shit!