I have never, and will never, segment my campaigns or ad groups by match type. Google makes too much changes to keyword match types, I’ve relied on grouping keywords with the same intent into the same ad groups.
I would group *”buy shoes”* and *[buy shoes]* in the same ad group as *”shoes for sale”*, and if the client only does ecommerce, I may also use *”buy shoes online”* in the same ad group, but those keywords should be separated from other keywords like *[buy mens shoes]* or *”womens shoes size 6″*., because those are more-specific searches with a different intent.