The dongel is necesary if you have no serial ports. Most new laptops omit them. The dongel coverts the serial output of your GPS to a USB input to your laptop. I own the Nobeltec not the Raymarine software but to my knowlege Raymarine uses raster charts. This was one of the reasons I chose Nobeltec. I much prefer vector charts.
P.S. My Nobeltec is used for planning and backup to my Raymarine chartplotter and radar. There is no way in Hell I would trust my self or my boat to a Windows based PC.