In some ways they're good. For example: if you need to call someone in case of an emergency; you can just flip out your cell phone and dial away, instead of using a phone at a buisness or paying to use the pay phone. And, if they're is an emergency and someone needs to contact you but you aren't home or near anywhere that has a cell phone, they can still get a hold of you.
But, then again, they're not so good. Like; when people are driving and talking on them or worse, they're texting. That's just dangerous. And, they're so expensive. They cost a butt-load of money. Moreover, if they don't and you only spend a little bit on them, they're crap.