This just tells me that their scummy monetization practices are working fully as intended. The whole point is exactly what you described; making players feel like they’re getting a worse deal when buying individual skins separately, thus making them more inclined to spend extra and get the overpriced bundle instead.
More people ought to stand up to Blizzard (and greedy companies in general) and make their disdain for 
-y monetization schemes ring so loud in the heads of people in charge that they are forced to change things.