Apart of the break in security issue, just hiding a decent amount of luggage under a cargo cover in a hatch is a problem. I have no idea how and why manufacturers are allowed to report luggage space for a hatchback, and what practical good those big numbers really are.
Case (
) in point. The Verano, which is a slightly large compact car, carries 2 suitcases, 2 aircraft dimension size carry on bags and a computer bag in the trunk. I took these with me when I went to test drive the BMW 240i, a small car in comparison. Because of excellent design to just fit these kind of items, it was able to fit both suitcases and one carry on. With the cargo cover on and the back seat up, which is how the car is used 95% of the time, our Elantra GT hatch will carry one suitcase and one carry on bag, plus a thin computer case with the cargo cover on. That's it. The Elantra GT is shown to have 51 cu. ft. of luggage space vs. 14 cu. ft. for the Verano.
Mind you the Elantra carried a box with furniture that was 7 feet long back from a store. The Verano couldn't carry a fraction of that size.