Because stripes can be very traditional, extremely contemporary, funky and fun or sassy and sophisticated.
I don't think the colour matters, the fact that you've painted or papered any area in stripes means that you have balls and don't mind that what you are doing is not 'safe'.
Who likes to be classified as 'safe' anyhow? Ga. Sies.
OK, so maybe you don't want to do an entire wall. Baby steps are good. Cushions, chairs, books (cover some books in stripe paper, place on your coffee table, it will look good, promise!) are a good way to start.
Image 1 via Collette Ward Interiors
Image 2 via Made by Girl
Image 4 via House & Gardens
All other images from the files, source unknown