I would say that "functional training" sounds nice but is really about frantic activity that gets you sweating.

Mark Rippetoe, author of the seminal strength training book Starting Strength, wrote in an article "CrossFit and Functional Training":

Strength, as you already know, is the ability to exert force on physical objects. Skill is the learned ability to carry out a task within a definable framework of time and energy.

Neither of these physical characteristics can be developed through methods that employ the constant variation of stress stimuli, because neither strength nor skill can develop under infrequent exposure to the stresses that cause the adaptation.

Like learning to play the piano, their acquisition must be accumulated in a logical, methodical manner. Not all exercise systems are equally proficient at developing strength and skill. As it turns out, strength training with barbells combined with practice of the sports skill is the best way to develop both.

Now that seems reasonable enough, right? You get both stronger and better at your sport over time, by training for strength and practicing your skills. So why are the two biggest players in the fitness industry telling you otherwise? [CrossFit and "functional training"]

and goes on to say

A tennis swing does not apply to baseball, or even to racquetball. A softball pitch does not prepare you for a baseball pitch. These things are obvious to anyone who has played them.

For the same reasons, a skilled wobble board squat with a light barbell may look impressive on the internet, but it cannot translate to a skilled field performance in an actual sport, unless the sport is wobble-board squatting with light weights.