? Triathlon bikes are not designed to be comfortable, they are designed to be aerodynamic, light, and to allow the rider to exert maximum effort against the pedals to get the most speed out of the ride.
Ironman does not care about you, how you feel or how good of an athlete you are. Ironman is a business, and the primary objective of businesses is to make money.
It is not cheaper to build your own bike and this is particularly true of entry-level and mid-level bikes
While race organizers do not require athletes to wear a race belt, the majority are specific about having the race number clearly visible in the bike and run portion of the race. While race belts are not mandatory in triathlon, they are very convenient to use as opposed to other options especially when wearing a triathlon suit.
What makes triathlons exceptionally challenging is the cost of joining, having the right mindset, enduring the run without getting burned out from the previous two disciplines, and finding the time to put in the required training hours every week.
There are many different distances for triathlons and more extreme versions are being created every year, however, the main 5 distances are Super-Sprint, Sprint, Olympic, Half Ironman (also known as a 70.3), and Ironman.