Statistically, I think you will see your "starters" playing in 90%+ of all innings, and "utility" players getting at least 75% of all innings - that is based on a team that carries no more than 12 girls.
For the championship game, I think most coaches have a #1 player for each position. They get that start. Up to crunch time, the "utility" player will get plenty of starts.
Those utility players are perfectly capable of starting and playing just about every game. They may just lack one component of being the top player for a specific position.
Maybe there are teams that follow the "starter" and "bench player" philosophy, but I think most teams are more fluid. The BIG difference is that a bench player may be competent in several positions, rather than specializing in a few.
My DD pitches, and plays second. She could play first if we needed her. She would not be a good utility player. I don't think she would make a good left-side infielder, and she does not have blazing speed, so in a 16U game, the only outfield position I would even consider would be right field, and that would be if no one was better. Another pitcher on the team has better speed, and could play left side in addition to the outfield. Except for the pitching, she would be a good utility player in her versatility.
So maybe that is the difference. A utility player is expected to be more versatile than a the next player.
I don't agree that a utility player is a second-class player. They are just used differently on many teams. They get plenty of starts.