The fact that an SMS costs money is a feature. That way people will think twice before they SMS you. Free communications is only great if you have infinite time to communicate, as the cost of a bit approaches zero the quantity of bits goes up considerably. Things that before would have been fine to save up until you meet again now need to be sent instantly, and need to receive an instant response as well otherwise there will be a bunch of 'did you get my message' messages to follow up on the first one.

I prefer a slight barrier before I'm interrupted and don't mind paying the cost of sending a message. On top of that I don't like non-regulated foreign companies looking over my shoulder. That this is a non-standard pattern I'm well aware of but it suits me just fine.