The trial scene in the finale seemed to last forever, an effect partially due to the endless flashbacks. Seinfeld has always been self-referential, but for the first half of its existance never used flashbacks, just references. (If I recall correctly, the first flashback shown was Jerry stealing the marble rye.)
My thought at the time was, "They've realized they're popular now, and people are watching the show without having seen these early episodes. So when they refer to them, they give a flash- back to help people with the context." In other words, they're pandering to non-fans.
That's what happened in the finale. Ask yourself how much better the trial scene would have been if they'd just shown the people's faces, maybe given them a few lines, but not shown flashbacks.
I know I would have preferred that -- would you?