@Christoph-Hart Thank you for your question. Just the kinds of things that lower-level access allows. I realize the struct is deprecated and may go away at some point.
Polling parameters (e.g., bpm and time signature) when needed, instead of keeping track of them with callbacks — it's a cool feature when you need to know when something has changed, but otherwise can be a little clumsy?
This may be my own issue, but the callbacks aren't being called at init. (They obviously work in your code example.)
Writing your own callbacks — for example, I want to show the user the seconds and samples of the DAW's playhead with high granularity—like the display in the MIDI keyboard. Another is example is doing calculations on the playhead in real-time.
The specific things in CurrentPositionInfo that simply aren't available in the Transport API, such as whether the DAW is recording or not.
