Speaking correctly, if they're at an increased risk of trauma, or they are beating the crap out of each other and will inevitably have to be crowned or removed because of wear in a much sooner than normal time frame, then fixing them is a indicated. Same as you would fix a broken ankle or herniated disc in your back. It's an objective problem that needs fixing from a health and well-being standpoint.

If it's a social or psychosocial issue where teeth are jacked up enough that a child is being teased or bullied or made fun of, then it's up to parents to determine if that's significant enough to warrant treating. Most parents care about their kids and feel that addressing such a situation with treatment is something a caring parent would choose to pursue. That's not my call, but the call of each parent.

If the crooked teeth are functionally fine and not a psychosocial barrier and they're just a little crowded or overlapped or spaced out then it's up to the patient (and their parents) to decide if that's something that they want to have fixed enough to spend the money on. It's subjective based on what they value.