Jph, looking good! I also wouldn't mess with it too much at that stage/age and let things develop naturally for a bit.
While true the only one of those people that actually throws far is Paul. Then if you look at most of the far throwers the disc is fairly stationary. I don't know for sure how much the pump factors into people like Philo not being able to throw far.
Just some form academia here:
I do think you can botch a pump and make it contribute to inconsistency/less power just like anything else in form. On the other hand a lot of very far throwers used it in some point in their development to master momentum, rhythm, and forces in motion, and it can play an important role in aiming when used well. One of the most important lessons I learned studying here was to study how far and consistent throwers initially developed their moves.
Note that there is a continuum from a full pendulum pump to subtle, tiny pumps. Simon and Paul both currently appear to have very subtle elbow pumps depending on what you're looking at. Both have also used versions of fuller pendula (Paul more horizontal, Simon more vertical). Koling also here, who interestingly probably is leaving a little on the table with his form but that's a slightly different story:
More older school examples: Stokely and Jenkins
If the disc is stationary, a given player's ideal move is just moving the body past the disc to achieve separation and load in the shift. If the disc is pumping or penduluming, it is contributing momentum to the move toward the target (and usually vertically to some extent), and the body and disc move synchronized past one another to achieve separation and load. The pendulum seems to teach players who have poor rhythm and momentum mastery some parts of form, and takes some of the burden off of the legs to create a weight shift because the arm/disc mass are swinging forward and then back.
I do think certainly full pendulum pumps are becoming less common at the top competitive level and I am aware that some coaches clearly dislike them (or simply don't use them). Sidewinder tends to advise them for people struggling with specific form issues. Some people seem to respond well, some of them never quite click. You can also find developmental examples that didn't spend a lot of time with pendula. I am still interested in the differences and implications.
Edit: per below, you tend to see more pumps when people are going for more raw distance - the momentum benefit of the pump builds more potential power on the rest of the above.
