It does matter, because "winning" at IG means you have an audience. Audiences can and will be monetized. I don't think this is that hard to see.
The reason so many people go so hard on the Instagram game isn't just to make themselves feel good or validated, it's because when you have 400,000 people watching your stories every day a lot of people will pay you to wear their gear while you do it.
Oh sure, ok, money. I didn't really think of that; it's all well out of my context. It's like sports. It matters like sports matter; for most people just a bit of fun, and for people really good at it, some money. It matters on an individual level for people who like it or make a living at it.
The reason so many people go so hard on the Instagram game isn't just to make themselves feel good or validated, it's because when you have 400,000 people watching your stories every day a lot of people will pay you to wear their gear while you do it.