A single shared nameserver does not grant a 100% uptime and costs 2x the price of the business plan that company I linked earlier is offering. I call this an expensive and badly implemented solution.
A single self-hosted nameserver does not grant a 100% uptime and requires a fitting internet connection and an old box to run bind on. At the moment I do not have an old box or server to run bind on, and even if I had it, the box could die and I would have to deal with the downtime (single nameserver), buy spare parts, lost time to fix the box and at the moment I do not have a fitting internet connection.
Godaddy's dns hosting is utter crap, it seriously hurts my eyes and needs a bazilion clicks to accomplish a simple task so I am looking for valid alternatives providing more than one nameserver, with uptimes close to (better yet: matching) 100%, to save money and time and keep paid and free customers happy.