In vscode when you step to the next statement it highlights in the left pane the variables that change. Something like that.

It's useful for a beginner e.g in a for loop to see how `i` changes at the end of the loop. And similarly with return values of functions and so on.

the intellij debugger, for example, as opposed to a command line debugger

Presumably an IDE rather then dealing the gdb CLI.

I think it depends on the debugger and the language semantics as well. Debugging in Swift/Kotlin, so so. The Smalltalk debugger was one of the best learning tools I ever used. “Our killer app is our debugger” doesn’t win your language mad props though.

I don't often need gdb, but I appreciate the emacs mode that wraps it every time.