As for books in particular - Kindle wins hands-down on convenience and portability for me, over bookstores (the 'walk-out' part is definitely covered). In my particular case, as I'm vision-impaired, Kindle ALSO wins hands-down on usability, because I can make the text any size I want. That's important enough for me that it can mean the difference between actually being able to read a book and not being able to read it.
I think I have 451 Kindle books. I can carry all of those in my pocket on my phone or in my backpack on my tablet, if I want. That's another huge advantage.
I should probably mention that given all that, I _still_ like physical books! I remember walking the aisles of Borders, but that was because they were huge and they had books in the niche I was looking for. I fondly remember a small bookstore that used to specialise in software development and IT books and they had a great selection of game development books. I used to love that place! For me though, that was all before I got a taste of the convenience of Kindle. Getting the book is worth more to me than stopping and having a nice coffee at the bookstore.