Anyone I've ever encountered that does the whole "I'm not using my phone, they aren't paying my bill" shtick(and it almost always is) wasn't driving truck before cell phones. Has no idea what it was like waiting in some tiny, hot, smelly "driver lounge" with 2 pay phones and a broken vending machine waiting to use the phone or for dispatch to get right back to you. Or waiting at the lunch counter of a truck stop for hours for a call back.
Maybe late 90s into the 2000s you made a stand with your cell phone, when you were paying an obscene amount for like 150 minutes a month. Now, you have a phone with unlimited everything. Me and wife are on a multi-phone single plan, have been since their inception. I've always added an extra phone, one for personal use, one for work. Not very difficult to do if you don't want work contacting you away from work.
It's a tool of the job. Many beneficial uses as guys pointed out above. And it's a tool you value if you remember how things were before their convenience in the industry outside of local type trucking.