There is another function of RDS that makes it very valuable for European national broadcasters.
Encoded in to the RDS signal is a list of the frequencies that a particular station is transmitted on. The receiver regularily checks which of the frequencies has the strongest signal and switches to that. This means, for example, I can drive the length of the UK listening to the BBC and never have to re-tune to another frequency, therefore reducing the chances that I will also change to another station. I don’t know if the US stations have the same form of blanket coverage that would make this worthwhile for them.
This is the real reason that stations use it.
Another aspect more useful for drivers is the identification of traffic reports so that the receiver can trun up the volume, interrupt CD or tape or record them for playback later
And the reason that I dislike many car radio receivers that use RDS. The damned things assume that if I change stations, then what I want is a new station with the same program - same DJ and music, different frequency.
What I want is a new station playing different music. The main reason I change stations is to skip out on some song I don’t like.
The radio in my Golf was really bad about that. You’d hit the button for “find a new station,” and it’d run through every alternative for the current station. Then it would go to a frequency scan and stop on the next frequency where it received something. From there, it would then do the RDS alternate frequency thing again. Repeat until you have a screaming fit. As far as frequencies were concerned, you might as well have had a random number generator in the damned thing. 105.9 then 88.2 then 98.7 then 90.1 Just fucking irritating.
I rarely watch TV, but I often look at Teletext for the latest news/weather/ etc. and to check if I’ve won the lottery(not yet).
However one very useful feature of Teletext is the subtitle service for the deaf.
Which is handled quite well in the US by the FCC mandated Closed Captioning system that has been in place since the mid eighties, at least. I know that I was seeing movies on TV with the CC blurb at the beginning back in 1985. It may have been even longer, but I don’t remember.