The point is, if someone has physical media that they have paid the same price for as you with your poorer quality (audio or visual) copy that's inly rental you are limited.
Why limit yourself with a product, when you can just wait say 2 days and have a physical version of a higher quality that is yours to do as you like with?
Is the quality in theory poorer quality? The audiophiles and the videophiles and the guys who look at things technically say yes - CD is better than m4p, blu-ray is better than video downloads.
On my definitely not audiophile or videophile equipment, enjoying it with my definitely not audiophile ears or videophile eyes, plenty good to me.
Higher price? Well, let's look at a movie just released, Hunger Games (not a bad movie, for those who care about my opinion. $22.96 Blu-ray cost on Amazon, $19.99 HD download from iTunes store. New album, Eyes On It from Toby Mac (no clue at all how good that is, my listening habits rarely go past 1980), Amazon CD is 11.88 regular 13.99 deluxe, 12.99 iTunes LP. For all practical purposes, it's a wash. Yes, there are bargain bins and special sales (and I do take advantage of them) but I'm talking "get the new thing"
And let me put my thumb on the scale a bit with some digital content that you may consider cheating: TV shows, you can get most episodes the day after, on DVD it's some time after the season ends. eBooks - hard to convert a physical book to an eBook. And Audiobooks - subscribe to audible.com and it usually blows away the price for audiobook CDs (plus they're one, sometimes two or three files you download, as opposed to lots of pieces.)
Do as I like - well, what I like to do is listen to the audio on my computer or my iPod or my iPad, and watch the videos on my TV. With my Apple TV, I can do that easily. With a couple TVs each with an AppleTV, each can be watching different video. Now yes, that limits me to Apple products - movies only on AppleTV, not on a Roku box. And in fact there is a minor annoyance I deal with - you can't play audible.com audiobooks on and AppleTV. That's a real disadvantage for some. It isn't for me, because I love my AppleTV, but if you have another box, you should look elsewhere.
Finally, rental. Well, I rent my Mountain Dew too, but I enjoy that. More seriously, while the definition of ownership is a little loose on this, I get most of the advantages of ownership - I can listen to things as often as I want, over whatever time period I want, without giving another dime to Apple. (I instead give many dimes to Apple for new stuff.) I've got a copy of The Incredibles that I bought in 2006 , watched it 9 times so far, and if I say two years from now "Hey, I'm in the mood for the Incredibles" I'll presumably be able to watch it (unless Apple goes bankrupt which right now I'm putting in the highly unlikely category). No, I can't say "I'll never watch the Incredibles, hey George, I'm giving it to you" - but I can't think of a time I ever gave away a DVD I bought to watch myself.
For my situation, my values, what I enjoy, the digital purchases are what fill my needs best. With things Apple has done in the past couple of years, allowing redownloads and such, it meets them even better. There are areas that Apple could do better and I'd like to see it happen (some way to transfer) but they don't change the final scoresheet for me.
For you, it may be completely different. You may have a more varied set of hardware than I do, that'll change things. You may have a far higher standard for audio or video, that'll change things. You may value the ability to transfer more than I do, that'll change things. I'm not saying that digital purchase are the right ones for you. I'm just saying that, rationally considering my life and what I like, digital purchases really are the better choice for me.