I have looked at the photos and blurbs of those magnetic blinds and it seems to me that they are suspended from two mall fittings fixed to the wall, one each end of the top, so you still need to drill for the fittings.
The magnets are just for raising and lowering the sections of the Roman blind bit - you get a pole to pull down the sections that are too high to reach, otherwise you just use your hands. That is how they made them cordless! Putting them up again is done by hand. Commenters on the Ikea page say that they can pull the blind down OK, but to open it again they have to stand on a box.
It also sounded (but it may not be) as though you don't get any rod to thread through the top hem to attach to the wall fittings. That wasn't very clear.
If I were considering these, I would contact Ikea with some questions before ordering.