Using MAP mode and the ADI ILS display. The localiser display on the ADI is by its design quite tiny compared to the HSI localiser display. 737 Classics.
If for whatever reason the aircraft deviates outside the expanded ADI localiser display it becomes a no-man's land because you don't know by how far the aircraft is off the ILS inbound course. All you know is you are more than one dot.
On the other hand, regardless of the expanded Localiser scale on the ADI, the HSI displays the full monty (all the dots) and allows the crew to see how far they are off centreline. This allows quicker situational awareness than the MAP mode in that a go around assessment is more readily available. Once the aircraft is even momentarily outside the expanded localiser scale on the ADI it becomes sheer guesswork to know how far off track it is.