As with work-related functions, I see no reason to acquire a mobile phone for that purpose exclusively.
But as a parent with kids, who these days in particular, only more and more seem willing to communicate via texting/cellphone exclusively, then obviously there's an entirely different aspect that must be considered. If you're not in that situation, then obviously that doesn't pertain to you.
Landlines will soon be a thing of the past. We might as well accept it, otherwise be on the outside looking in. That's where things are heading, just as computer technology has also made normal correspondence via written letters nearly obsolete. To deny it is just refusing to accept reality of where we are.
I'm inclined to take the good with the bad and stay in touch with my kids. With work, however, it's an entirely different situation and I understand fully the usual grievances. It just comes down to what one is willing to accept and/or sacrifice.