The majority publicity about the (practically non-existent) security threat in Skype for Android means that the big push to get user to upgrade was based on security concerns.
However, it also included an important, though less publicized upgrade which allows Skype users to make VoIP calls over 3G. So if you are on a plan with a large data allowance and costly (or limited) call minutes you can now make them using VoIP on your 3G connection.
The most exciting part of course is that this is a step towards the really big upgrade that we Android users are waiting for – Skype Video calls over Android. This has been expected to appear at some point ever since Skype bought Qik, which was a mobile video calling company. Skype Video over 3G will finally give us the reality of the “Video Phone” that we have been seeing in sci-fi movies for decades. Sounds like fun!!