Well, space tourists are likely going more for the 100km view and the zero-g experience, which is present for a few minutes on a sub-orbital trip. Given that you can't get this experience anywhere else, a few minutes is better than nothing.

The exiting of the atmosphere is part of the view [1], but it works in concert with the altitude. Trampolines, as far as I am aware, are incapable of propelling one to an altitude that provides such incredible views :)

[1] https://www.nasa.gov/multimedia/imagegallery/image_feature_1...