If comparably equipped the difference is more like $4500 not $7K. As you menioned, the F30 gets power seats, but also iDrive, heated rear seats, rear HVAC vents, and ambient lighting standard. Also the quality of the interior parts is noticeably lower in the X1. Note that the seat desigs are different as well. Why the paddles are only offered with the Sport Line and M Sport is beyond me. It's likely a way to encourage them into a package. The F30 has more interior passenger space and maybe they can command more for that.
Remember that they didn't introduce the X1 to US until this year because they couldn't make as good of a profit on them as the ROW, but now they have the capacity and can accept the lower profit. If you can sell a car for a lower profit without impacting the sales of other models, why not?
As others have said, it comes down to what the market will pay, and they will ask what they can get. All models have acceptable profit, but why not a fatter profit, if people are willing to pay.