Now that group video calls are free for everyone, we’ve removed Premium to give it a refresh. But don’t worry, you can still call phones worldwide at great low rates with our subscriptions.
I purchase Skype credit and use it when I need to call companies in other countries. It's very inexpensive. I've also used their feature that let's you attach a phone number to your Skype account before when travelling.
There's Skype Numbers, as it's now called, you buy a phone number for $5/month (in the US) and where ever you are, if someone calls that number you can receive the call using Skype.
My mother and myself are not serious cell phone users, and we use < $40/year subscriptions to make all our US long distance calls, and many local calls (she's 77 and has lost a fair amount of her hearing, so the high quality of Skype calls and flexibility of using a good headset is particularly appreciated. I also like those features).
We keep waiting for Microsoft to screw it up, but they amazingly haven't so far.
though i don't have a premium subscription, i buy skype credit to call my parents in south asia, them not being that tech savvy, i have to call to their landlines/mobiles). for me it's a seamless process, as i can call directly from my computer, or from the app on my mobile if i'm out.
As an extra feature for Microsoft, I'd bet so. I know plenty of people who listed Skype support as one of the big reasons they got the Xbox One. (Skype on the One is part of Live Gold, which is about $60/year)
As well as using it to call international numbers, I also use it for Wifi access at some airports.
No doubt I could do both more cheaply another way, but I do them both so rarely that Skype just already being there "and just working" is great. I pay at most £20 / year.
Skype pulls in a lot of revenue in the OCS/Lync product set. Companies want still largely want to be able to IM MSN, Yahoo, Skype, and AOL users and they're the only ones that have access to all those user groups. They also leverage B2C video/calls to Skype users.