Yes, there were way more efficient ways to store video on the go in the 2000s, like MiniDVD players with tiny screens. The codec is in firmware and the video format and medium is standardized. It’s the easiest way to sell small, cheap gigabytes of storage if you need no quick random access. And the family might already have the more useful laptop-like portable DVD player with a full-sized drive and almost every home video title was available on those.