For me, I love the classic red-and-white Poké Ball. I love the uniform look of a party of six all in that clean, iconic capture device. Others are a little more particular about which Poké Ball they use to capture their Pokémon. Some want the balls on their belt to be aesthetic. Catch your favorite fairy-type Pokémon in a Love Ball because it’s pink and you want to make Margot Robbie’s Barbie proud. Use a Dive Ball on your favorite water Pokémon because it will remind it of its sea home that you stole it from.
But don’t tell a Pokémon fan you just use whatever Poké Ball you have on hand. Quick Balls are effective for catching a critter right at the beginning of a fight, but they’re ugly. Don’t just chuck a Heavy Ball at a Gastly when that thing is weightless and you could use that ball to capture something heavier. These balls have inherent effects that make choosing which one to use a big part of the strategy, and they’re a small part of the expression you get because it’s part of the customization. But shit, sometimes you’re 50 Ultra Balls in and you’re just tired and start throwing out whatever’s in your bag. Your Poké Balls are ugly but it was an ugly, arduous process to get the little shit to stay in the ball.