I received several mystified emails: surely you made a mistake that this chant you call Laetare Jerusalem is suitable for the processional? My answer is: not only it is suitable; it where the day gets the name. It is normative because it is the first choice of the GIRM, which is consistent with Vatican II's placement of Gregorian chant as primary, and, moreover, is the only introit to grow up alongside the existence of the day itself. So not only it is suitable and normative; anything else, and least of all some random hymn with an entirely different text, doesn't quite do it.
I like this presentation because it is unadorned with accompaniment, and it happens to be beautifully sung as well.