If Sora can get you there with basically no speed penalty, and only slightly slower shifting, but at 1/6th the cost of DA, I don't think you can say DA is a better bang for buck, even if you like the way it handles much better.

When it comes to how much you're willing to pay for crisp shifting, ergonomics, etc., the sky's the limit and there's no answer. But in terms of bang for buck dollar for the actual measurable performance, Sora or other entry Shimano parts are the winner, even if it's not something you'd use yourself.

I drive a midlevel car even though econoboxes are the most cost-efficient and highest bang-for buck. Same argument.