Very typical for cable companies - this tactic is called Bait n' Switch. They want you to sign up for Home Phone because, in most cases, they are paying a per subscriber fee to use the network and pocket the difference. Time Warner Cable, for example, had a partnership with Sprint for Home Phone.
Also, don't assume that in case of an emergency, if your cell phone will not work due to an outage of the nearby cell tower(s), your home phone will still work. Today most home phone plans are VOIP, so if your Internet is down or the phone battery is dead and there is no power to charge it, you will not have your home phone during this type of emergency.