While we don't have a specific policy regarding link/video only questions, we do have one regarding answers.
Provide context for links
Links to external resources are encouraged, but please add context
around the link so your fellow users will have some idea what it is
and why it’s there. Always quote the most relevant part of an
important link, in case the target site is unreachable or goes
I think the logic behind this policy applies to questions equally well.
It's certainly feasible that this user could take down the video or delete their YouTube account. YouTube could change their link structure, or (admittedly highly unlikely) YouTube could fold entirely.
Whatever the case, we want the question to provide value to future users. That being the case, I believe that any link or video should provide textual context, whether it's in a question or an answer.