Up until recently all comics sold on Comixology were DRM free, so you could download them and do whatever.
So with that in mind, they were as "physical" as a DVD... If that's where you wanted to store them.
However I could also have all TF comics on an iPad wherever I went which was nice.
Needless to say, from now, they will no longer be DRM free.
Also:
1) store is gone. Need to purchase through Amazon which is terrible.
2) app is gone. Need to read through Kindle which is terrible.
3) Subscriptions no longer work outside of the US.
4) Wishlist's lost.
5) Smartlists gone.