I would also like to point out that a Shield isn’t exactly permanently attached.
I’ve worked places where we would watch movies or shows on the night or weekend shifts. A Shield TV with 500GB of media synced on it could be used where corp wifi blocks Plex or cell signal isn’t that great.
You could also sync a lot of stuff onto one before a family trip somewhere. 500gb worth of media could go a long way to keeping bored kids occupied while you help aunt Gertrude get ready for her wedding.
So, yes, there are plenty of reasons to put sync on the Shield.