Why it is important? This is because notifications are passing through the Apple (for sure) or Google (not sure) servers.
If only Microsoft did the change to the interface, making messaging more visible. Most of people I do speak by Skype do not know that Skype messaging do exist. When I ask to open my messages they don't know how to do it.
And of course I think Skype is mining bitcoins on my PC, as it takes lot of CPU and even more I/O when idle.