+1. After my first IM and realising how my swim kind of tanked my bike and run in terms of missing any group, ive been a bit more focused on swimming, moved from no proper pattern 6 beat mess to a consistent 4 beat and it's a game changer (for me) as it balances the benefits of hiding adult swimmer rotation / body position flaws like 6 beat with efficiency and energy savings of 2 beat; easier also to handle waves tempo changes and sighting especially when no Wetsuit. Legs feel way fresher.

I swim with someone who did total immersion 2 beat class, and from what I can see fixed some rotation issues and added a slow 2 beat kick but without a good catch pull it's still slow and worse for tempo changes and rougher water I suspect. So not sure unless u have strong catch and good technique.

Another guy who is a much better technical swimmer swims 2 beat he smokes me in the pool but I can swim same open water than him now in right less perfect conditions (for me not for him), in smooth water between sighting he'd do well 2 beat then maybe needs to change to something else around bouys, waves, congestion, sighting etc. I'm no fish though, as an adult onset swimmer basic 4 beat and at least 12-14km a week 5 days a week swims is what is needed so my lousy technique can be covered by solid endurance enough to then have mental focus to think about what I am doing rather than drowning. Training volume and not huge technique flaws can cover up a lot of mistakes.