The Bigscreen beyond requires a face scan and generates a custom interface to fit each persons face perfectly. Everything I've read indicates that this actually improves fit and comfort. It helps that the bigscreen beyond is incredibly light and small, but the face scan doesn't seem to be a gimmick. The Vision Pro might end up a complete failure, but requiring an appointment and a face scan is not a sign for this.
While the personalized parts can probably be bought for a whole household and swapped by the user, when including lens correction for instance it's just not practical and it becomes a single owner device.