What wire are we talking about?
Analog telephone lines that run devices like your fax machines, modems, credit card machines and more. The #1 reason to make changes to how these device connect to your network is COST SAVINGS. Carriers have been marking up these analog lines for years so if you still have them you likely paying too much. There are ways to move those types of services to more internet based or bandwidth driven solutions. Who isn’t interested in cutting costs?
Cat3 cables (wire) inside your business. For decades now most businesses have a wallplate by each desk labeled data and voice. They historically were separated, and many businesses that are Living On a Prayer until that old phone system dies you may still be using it. The 21st century would like to invite everyone to just move over and just use that data plug, and new phones can do that. You’re already “Halfway There, whoooaaa ohhhhhh….” There are cost savings to be had here in not having maintenance on two separate infrastructures. Again, who isn’t interested in cutting costs?
The biggest PRO in upgrading these is future proofing your technology BEFORE it dies or becomes obsolete.