Hi shaselai,
Are you talking about Stern? NYU is probably most known for the required on-campus interview. Certainly Tuck and others ask for a similar voyage - it is usually when they want you to come see what they are all about; to experience the community that they have on display. Doing it over phone/Skype is probably going to be fine for showing the school who *you* are, but they don't get to message back to you in that format. This means that you have to work extra hard in your interview to ask good questions, to show interest ... just to bring the "fit" right to the surface.
The phone/Skype option is clearly there for people who simply can't travel that kind of distance or under time constraints, so it should be used accordingly. If you can get to the school without killing yourself, you should do so. If not, know they wouldn't offer the alternative if they were going to discount it - just be sure to bring your A-game if you are doing it remotely.
Respectfully,
Paul Lanzillotti