apart from the fact that he wasn't any faster, he was evidently struggling with his TT position on numerous occasions, not to mention having no power at all whenever road went slightly uphill, is there any reason behind training on a TT bike (instead of a 'regular' road bike) and racing on one?
Sounds like a poor fit. It's not uncommon for there to be a slight power loss going from a road setup to a TT setup, but the substantially better aerodynamics more than make up for it. Also, he could just be slow
TT=aero, i get that, but in the real world, with traffic, junctions, wind, rolling terrain, is riding on such TT bike anyhow beneficial?Yes
Setup Estimated Ave CdA (m^2) Speed (km/h) Power (W)
Tarmac SL2 | road helmet | drop bars 0.310 40.10 306.6
Tarmac SL2 | road helmet | clip-on aero bars 0.267 40.27 268.6
Tarmac SL2 | TT2 helmet | clip-on aero bars 0.256 40.38 261.0
Transition | road helmet | aero bars 0.265 40.17 262.9
Transition | TT2 helmet | aero bars 0.230 40.05 229.0
Traffic/Junctions/Hills aren't particularly common in the races (at least compared to road races), so it's still beneficial to put some training time on the TT bike, even if you aren't just doing flat intervals. Professional cyclists still overwhelmingly choose TT bikes, even on rolling/hilly TT courses (See: ToC TT stage this year, almost all TT bikes despite a substantial climb at the end). However, I do think a lot of triathletes spend too much time on their TT bikes and not mixing up their training on road bikes with groups (to gain handling skills if nothing else)
what about this awkward position that apparently isn't best suited for other than plain flat roads? last but not least - don't triathletes, despite triathlon not being a team sport, ride in groups after all..? can't they just suck a wheel, like normal roadies do..?
Draft legal triathlons are typically reserved for ITU Pros (A specific type of event, any WTC Ironman or other race still has the pros maintain distance). Of course TT bikes aren't as easily handled as road bikes, so they make sure to require some space between competitors. Amateurs are required to have about 23 feet (7m) between them. Even if you took away the TT bikes to make it safer, and allowed drafting, it would completely negate the purpose of the bike portion of the race. You'd have everyone swimming as fast as they could to not "miss" the pack as it left the transition area, then you'd just sit in and wait until the run to make a move. Draft legal triathlon would be incredibly boring to participate in if you weren't a phenomenal swimmer.
Triathlon is a bit weird to be honest; most people who consider themselves triathletes have probably participated in a race of some sort, whereas with cycling, a very small subset of people you see out on bikes have ever raced. And even amongst the people who do races, because it's an individual sport, you have some people who are very competitive, and some people who just want to finish in the allotted time.