Tesla use different systems for visualisation of traffic data and navigation routing. Navigation routing is always available and part of package, traffic visualisation is part of premium connectivity package that costs £9.99/month after the trial period, 1 or 12 months depending on the car.
Personal experience is that visualisation often shows traffic where there is none, even late at night. Its routine to come across an empty junction and visualisation showing it as slow traffic.
Navigation seems to do a fair job of taking traffic into account, but as its not linked to visualisation, you often do not know why its taken a preference for a particular route.
Only use for me for visualisation has been when getting stuck in a motorway jam and wanting to get a rough idea of how long it is. When there was a threat of us losing premium connectivity (long story affecting early adopters), I must admit I would have missed the live visualisations even though I don't trust them with any accuracy. But I wouldn't have paid £9.99/month for it.