Though the NAV maps and routing in your Uconnect aren't as good as other offerings in your phone as others have stated and you can easily experience for yourself. I personally still keep my maps somewhat up to date in my vehicles by catching sales, other vehicles that take sd memory cards you can get one step later versions online cheaper if you don't try to keep exactly up to current, etc. Just so the map isn't 3-5 years or more too old. If daily driver, I might get tighter than that.
Reason is for me, is that some areas I travel in/to don't always get cell phone signal so when you use NAV maps in your radio they use a different signal antennae that is built into your truck, which almost always works everywhere. Especially in areas where cell isn't, like some of US national parks, lakes, etc. Depending on where you live and frequent this may or may not be an issue for you. But for me, I'd rather have a map and navigation showing me where the closest road is then no signal at all.
Yes, you can download maps to your phone and use navigation offline of a cell signal. I just don't always remember to do that before I take off, so having NAV in vehicle fits me better. Btw, as far as downloading maps and taking them with you....I just got an email from Google maps today reminding me my downloaded maps are too old for the roads as they are today to be of significant use to navigate by. To me all this depends on preference.
Want an interesting read, go read up on China developing their own GPS system with their own satellites. For which NAV systems utilize in vehicles with navigation/maps. Big changes coming all around us. I've never heard of a $600 fee either btw. Must be a new price gouge approach.