OK, I think I see what they’re saying. The HD traffic has some specific detailed info about the local area you are in. So, evidently it might show a message “stalled car in left lane ahead” where the smartlink traffic would show an incident but might not specifically say it was a stalled car.
Or at least that’s what it implies to me. Like I said, I use the StreetPilot app that I think is the same as smart link traffic. Driving around NYC the traffic info is usually very accurate and you can see it updating in real time on the map as road segments change color. The old style TMC receivers were basically useless in the NYC area, and there were also long stretches of the NJ Turnpike with no traffic reception. Pretty sure those same sections wouldn’t get any HD reception either, you have to be close enough to one of the FM radio stations the broadcast the data.
I used to commute over 100 miles daily and the FM traffic receiver was pretty useless for that. There was no reception for the first 25 miles of my commute, and by the time I got a signal it was usually too late to pick a good alternate route.
If most of your driving is in an area where you can receive the HD traffic, it may be a good solution. In the past, I found Garmin’s traffic reception maps to be “optimistic” at best. 😉