Actually this is not a very good technique.
You are not supposed to rest your finger. If you watch famous guitarist, you 'll probably see that they follow this technique, but they only use it while performing, and, I guess, without noticing it.
For example, Jimi Hendrix, Eric Clapton, John Frusciante, etc.
But of course you know you are not Jimi Hendrix, and even these players, I believe try to avoid resting the little finger while they practice.
If you want to check what's the best technique, you should definitely see videos of great Jazz player, who usually have an excellent technique even while performing.
For instance, you can check Scott Henderson giving tips in this video:
Check his picking hand! ;-)