There are plenty of places where radio & GPS-based time services will not reach. Another benefit of an NTP clock is that you can control what it's sync'd with, since businesses may have other systems (point-of-sale, etc.) that are not precisely sync'd with NIST coordinated universal time.
I ran across these a couple years ago, when I was looking for just such a product. I love the old-style red LED display and the boxy industrial construction. Even the fact that it displays seconds is a plus. I couldn't find an "atomic clock" remotely like that. However, in the end, I was put off by the price. I just couldn't justify it for home use.