No, that would not be the appropriate comparison at all.
That is the comparison that is more similar to loot boxes, but not to the definition you have decided upon.
Loot boxes give you variable entertainment, but for that to be gambling you have now defined entertainment value as the element of prize. Gambling requires chance, prize and consideration.
https://www.lexology.com/library/detail.aspx?g=e7b39fc2-501e...
At the point where entertainment value is the prize, you have now created a definition of gambling that includes both your example of a random movie, and my example of any movie.
The thing I hate about all of these lootboxes as gambling arguments is that they have no appreciation for what gambling actually is. Instead gambling is now just whatever you feel like is gambling in your gut, not an actual real legal and enforceable definition.
You want to regulate lootboxes, fine, but trying to draw an equivalency to real gambling and lootboxes is just not possible without classifying almost every transaction as gambling.
But honestly, if you want to regulate loot boxes we should probably start by regulating video game addiction because it is a much larger problem that effects a much larger audience.
All of these deeply concerned people who want to regulate loot boxes somehow don't seem to overlap with the group of people who want to regulate video game addiction though. Because the deeper truth is that people want to wield the tools of government like a cudgel to force video game developers to make the kind of games they want.
This whole thing is just a fig leaf similar to how child porn is used to censor the internet and enforce copyright.