Following is Pogue's last word (of 2011) on the subject in today's New York Times:

MAC APP STORE Apple has decided that the DVD is dead. The future of video-watching and software-downloading, it thinks, is the Internet.
To that end, it has created the Mac App Store, so that we can buy our computer programs the same way we buy iPhone apps — by downloading.
The idea has some overwhelming advantages, at least if you have a fast Internet connection. You don’t worry about viruses or spyware. The installation is instantaneous; you’re not even asked for your Mac password. You never have to install patches or updated versions; the version you’re downloading is always the latest. You never have to hunt for the original installation disks; the App Store is a storage locker for everything you’ve ever bought, and it’s available from any machine.
The Mac App Store makes the old methods of software distribution look as antiquated as eight-track tapes and carbon paper.