The trick to printing digi papers is to use a photo quality paper. I use 3 different kinds: matte photo paper, presentation paper, and brochure & flyer paper. When using these types of papers, they will stay vibrant just as if you had printed a photograph. Most inks & photo papers are rated to last about 100 years when stored properly. I'm sure that's long enough for any card.
If you want to take a peek at my gallery, you will see that a lot of my more recent cards are made with digi papers I printed out.