Would love to see a video of what this actually means. I'm not sure I've ever written code for which I can use a REPL in any meaningful way so I must be doing it wrong. Videos of actual real world coding/debugging (not examples that are too simple and therefore not real world) would probably be very enlightening.

I mostly do graphics stuff and there are 70 lines of setup until I get to the 1 line that executes something based on the 70 lines of setup. But even in non graphs code my program 1000s of lines, all of which have to execute where as a REPL is one line at a time so yea, a video would really help see how to apply this.