That's a good point--"it depends"! It depends on how many times you want to wear a given item per unit time vs do you need more variety.
The negative origin of splitting wears is that you find you are not wearing something enough to justify its cost or place in your wardrobe. So it's not wrong per se, it's that I may want to try to get a lot of use out of an item.
Our entire wardrobe could, in fact, be reduced to the concept of splitting wears--for example, having a "10-item wardrobe" for 3 months means a lot of repeats but fewer items, less clutter, perhaps able to spend more on each item; 20 items, half the repeats (or whatever % distribution) and so on.
But, if you have a very small wardrobe and find you want/ need more items so that you actually don't have to repeat as often, then you will "want" more similar items for that purpose. That's why splitting wears tends to focus on the negative, in cases where you already have "enough" of something and you want to think, do I need to add, or am I tired of one and want to replace, or do I really just not need any more?
I think it's most useful for being mindful that each item purchased then in theory means less wear for existing items--is that okay, or is that not what was intended? Also good for the idea of fashion updates; if I have a lot of sweaters, I might find I can only wear each one once or twice during the winter but am storing a lot in the off season, and then if somehow am ready to shift to a different fit or style, then I've got a lot invested in my existing sweaters!