The morning with bicep curls

I must admit to something – I hardly ever watch other trainers in the gym but as I was just relaxing after finishing my morning training I heard 3 intriguing words ("sport specific " and "triathlon") . I train a few endurance athletes but I still find that training is an ongoing learning process. Every single session, month, year can be a surprise, things that should work - don’t, things that theoretically shouldn't – sometimes prove to enforce the right adaptation, etc. Therefore every time I have a chance to watch an s&c coach working with their athletes, I always try to understand their methodology and pick up some new ideas, which once they are stolen I count as mine. This morning, I failed to understand any logic behind the training I watched. I witnessed (spied on) someone calling himself strength coach training one of his clients. From the conversation they had I knew the trainer's intention was to prepare his client for a triathlon. Guess what a fantastic functional exercise occupied about 15 mins of his (1 hour) session with the trainer - BICEP CURLS! Done different ways: standing, preacher curl, famous 21's etc. Whoooohoooo!!! Before the biceps they did some "chest" on the bench, I counted 4 sets of 10 reps. I could hear the trainer telling his client how well he will do in the upcoming event. Well...if his training looks like today’s session every time, he will need some serious amount of luck to even complete the race. Will the curls and bench make that poor guy run or cycle faster - I doubt it, maybe they will make his stroke more powerful? - have no idea how, but ... who knows... The mystery of the purpose of that session remains completely uncovered to me. If anyone can explain it to me – I will truly appreciate it.
Saba