Once upon a time, I would've agreed with you... until I heard that Epic Games got in trouble for trying to create a culture in Fortnite that shames and bullies kids for using the default skins. The advertising around cosmetics is as psychologically exploitative as battle passes and the like, and though they lack the same addictive qualities as lootboxes, they prey upon the same people - namely, kids and those with mental health issues that make fiscal responsibility difficult, like ADHD.

Plus, Blizzard has a history of making in-store items higher quality than what you'd find in the game, so it does affect gameplay in the sense that you get lower quality stuff in the game as a result. Plus, look at what they did with the original Overwatch skins being paywalled when they forced people to switch to Overwatch 2. Blizzard deserves no benefit of the doubt here.