My guess is that applicants who are located relatively close to Yale got invited for on campus interviews. International applicants and applicants from further afield got these video interviews.
I don't believe that every applicant who did not receive on campus interviews has been invited to submit video interviews. The head of admissions congratulates you for making it to this stage of the process, implying that some people have not. I don't think that he needs to lie. @ NYYankees, Yes they may be testing the software but I honestly don't think that they play secretive games and mess with their applicants emotions as that would only be bad for the school in the long run.
Normally schools give one of the following: ding, WL with interview, WL without interview, accepted with interview. There will still have been some applicants who are dinged and some who are WL without interviews, why would the Yale adcom make more work for itself by inviting these people to submit video interviews?
I think that if you have been asked to submit a video then you should look at it as a positive sign that Yale are at least interested in you.
It looks to me like no-one who has had a video interview has heard anything yet, have a little patience and see what happens.