Very useful if you want to video skype someone abroad and want to find the best time of day.
No, its not good for that. Nothing is good for that.
Skype is a peer-to-peer network.
In order to get from A to B, it builds a network of nodes that consist of other people's installations of Skype. There is no way of knowing what path your traffic will follow at any second of the day, and there is certainly no way of guaranteeing it will follow the same route the next time.
Skype run no servers themselves other than for back-office stuff (authentication etc).