In order to classify an exercise as functional, it should carry over to everyday life. Squats, pushups, and pull-ups are often lumped in the functional category because they integrate multiple muscles at once and display bodily strength. However, how often in your day to day movement (away from the gym) do you really use these movements?
Day to day, the human structure moves through contralateral patterns, like walking, more frequently than a squat or push-ups and pull-ups. From a biological standpoint when the body encounters a flight or fight scenario, mechanisms activate in your body that cause you to run from danger- another contralateral movement.
Instead of categorizing exercises as functional just because you aren’t doing yoga or meathead bodybuilding and powerlifting, you should consider how much carry over that exercise will have in life outside of the gym. Will it help your mechanics when you walk and run, or will it sound and look cool but really not have much impact on how your body moves most?
Functional training, when done correctly, will build muscle and strength that translates to movement patterns that your body uses on a daily basis. The stronger you are at what you do most, will result in more efficiency and less wear and tear on your body.