Competitions & Breeding prospects

[Slaptail]

I've noticed that people will take 1 horse and put it in almost all of the different competition types. Is there a reason for that? Wouldn't they get more successful horses breeding different "lines" (so to speak) with different conformation that would help them excel in each discipline?
Or am I not understanding how the breeding works?

Is the conformation that adds to the horses ability based on that specific breeds standard? Or is it based on good conformation alone, regardless of breed?
It is really hard for me to explain, but basically what i mean is say you have horse breed x but instead of breeding to refine the typical build, you cross to make it more suitable for x discipline. Would those be faults/no benefit for that breed specifically, because it isn't the typical standard for it? Or could you basically take a breed of horse and shape it by crossing to give you many different builds that would work for many different disciplines?

[Argent II]

You can enter a horse in random competitions and maybe get lucky with placings, if it's relatively good. It's a matter of collecting more points, wins, and earnings and it doesn't impact a breeding program negatively to test horses in different sports.

Conformation has nothing to do with breeds or breed standards.