Don't drop your POTS line altogether.
Generally, the cheapest wired telephones work in emergency situations since they are not dependnat on power suppklied by your house. They use power supplied by the phone company. As long as the lines are up, they generally have a good chance of working.
If your power goes out, so does your internet line. No cable TV, no internet and no phone. And, even if you're using phone line supplied DSL, your modem is out as well with no power.
Keep one phone with at least minimal service, just in case.