The one advantage is that the old phone lines have been proven to be very reliable through a lot of times where something like a 4G connection hasn't. I used AD

The one advantage is that the old phone lines have been proven to be very reliable through a lot of times where something like a 4G connection hasn't. I used ADSL as a backup for times when 4G was unreliable, like extreme weather situations. On the other hand, once line noise reduces your speed to kbps rather than mbps, they're also of limited use in this day and age.