When Mac OS X Lion was first announced, it was also mentioned that unlike the previous incarnations of the operating system, it will not be available in CD format, which meant that users who wanted to install OS X Lion will either have to download it or get it on a USB stick, which costs about double what the downloadable version costs.
While I can’t speak for the masses, having a USB stick containing the operating system will be handy when you want to format the computer and require a reinstall. This is definitely a much quicker and more efficient way than downloading, especially for users whose internet may not be reliable or if they’re continuously on the go and may not have a fixed/stable internet connection.
The good news is that Apple has reportedly started shipping the USB sticks containing Mac OS X Lion 10.7 and it will retail for $69, so for those who prefer a physical install, you should be able to purchase the USB sticks pretty soon. Alternatively if you already own Lion but would prefer a physical backup of the operating system, the Lion Recovery Disk Assistant software could be an alternative worth checking out.