Hard copies of movies--DVDs--are your best bet. The problem is your kids/grandkids probably won't want them, may not even own a DVD player. Though perhaps one day DVDs and CDs might make a comeback like vinyl
It is rolling the dice "buying" digital as anything can happen to these companies down the road and digital content will be lost. That may be the best thing that could happen. A big company goes belly up and millions of dollars worth of content disappears and consumers wake up to the reality of the problem. Except it doesn't even have to come to that, hackers could merely take over a big company's servers and either destroy or hold hostage everyone's content.
And then there is nonsense like this:
https://www.yahoo.com/tech/reclaim-f...163742946.html
And this:
https://lifehacker.com/near-unlimite...tti-1756413619
And this one really stung:
https://betanews.com/2012/08/20/your...ion-has-ended/
You never know what these companies may do. It is bad to be at their mercy.