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It started going into a lot of mass production engines in the mid to late 2000's. My understanding is that the forces on a piston are highest during the power/expansion stroke, so by improving the angle during that stroke you can cut internal friction pretty significantly. It also saves on piston ring and cylinder wall wear.
It doesn't show up in a lot of high revving engines, or those in luxury cars. My guess is that it's harder to balance, if that can be done at all.
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