Most of my bike are of mixed race. Since I'm a big guy, I like large cassettes in the rear mixed with my road bike front cranksets and derailleurs. So I end up with large 11-32t cassettes in the rear and long cage mountain bike derailleurs and road bike stuff up front.

The only real reasons to upgrade to stuff like Dura Ace is shaving grams off your bike so you can get a competitive edge and lose a thousandth or few off of your lap time.

Some dura ace components like Dura Ace cassettes wear a lot faster than say a 105 cassette due to materials used.