I'm surprised to see nothing on this thread about Movies Anywhere. You can use it to meld the IRL DVD purchase with the online ease of access - https://en.wikipedia.org/wiki/Movies_Anywhere

If you buy the DVD, you get a little code to enter in the Movies Anywhere site/app. Once you do that (and connect your account to Apple, Google, etc.) then you can access the movie you purchased anywhere.

I've done this a few times - I buy the DVD but never actually watch it. Instead I have it registered with Google Play and watch it that way because it's just more convenient with my TV.

KEY - NOT ALL CONTENT is available this way. But enough is to make it a pretty nice experience. (Movies Anywhere is owned by Disney)