I realize this question is niave, please go easy on me! :)
I don't have a background in competitive swimming and one of the things that confuses me is the contradiction between racing your own optimal pace and racing against the other swimmers in the pool. It seems like swimming with your own optimal pacing should always be your best option. The only exception I can think of is for a slower swimmer to use tactics which attempt to get a faster swimmer to blow their race. This doesn't seem to fit in with the general principles of masters swimming, so why do the higher level competitions seem to cater to it by seeding by other than time?
If a person always stuck to his own pace he would never go faster. Sometimes it takes some good competition to push you out of your comfort zone. I am remembering an interview of Kaitlin Sandeno after her silver medal swim in the 400 IM in Athens. She was second by .12 in a very exciting race, going a 4:34. Afterward she said she had been "stuck" for a year at 4:40 (we should all have such problems!) and was thrilled to take off six seconds. That was definitely a break-through swim for her and I guarantee would not have happened in a time trial without the close competition and the Olympic medal stakes. To take off that much time at that level is enormous.
If a person always stuck to his own pace he would never go faster. Sometimes it takes some good competition to push you out of your comfort zone. I am remembering an interview of Kaitlin Sandeno after her silver medal swim in the 400 IM in Athens. She was second by .12 in a very exciting race, going a 4:34. Afterward she said she had been "stuck" for a year at 4:40 (we should all have such problems!) and was thrilled to take off six seconds. That was definitely a break-through swim for her and I guarantee would not have happened in a time trial without the close competition and the Olympic medal stakes. To take off that much time at that level is enormous.