While Sony calls it "ending support" the result is still the same. Without Maps you will lose the ability for the Vita to obtain your location or display maps. As for the YouTube app, you can't download it any longer as of today, but although you will lose some functionality you will be able to watch YouTube clips within the browser, so it is not a total loss.
While Sony isn't saying why they are removing the apps, we suspect that licensing is the likely problem and there simply are not enough people still using the applications for Sony to continue to pay to have them on the PlayStation Vita. While it will be sad to see the apps go, we suspect that this will not be the last of the apps to depart the Vita.