My understanding is it does need to be connected to a digital interface. EITHER digital gauges, or for instance your Simrad, or both if you have both of them.
Correct me if I am wrong, but you have analog gauges with have a Simrad gps/fish finder. Your NMEA should be able to connect to the Simrad and give you more read outs through that. I’d follow back up about checking that connection. IF the NMEA and Simrad were on the boat at purchase as part of your order through Bennington, getting that resolved should be covered by warranty. If either the Simrad or the NMEA connection were after market add ons, then I would expect that it’d be on you.
That said, I believe one would otherwise normally connect their NMEA to digital guages. Fortunately, with your Simrad, you basically have a large digital display now, and it should interface if a) hooked up properly, and b) all components work.