Even though this is about mountain running, as is your case Whiteroserunning, many of us do not have regular access for our training. The best I have is a small ski hill with 48 m vertical for 250 m distance, which takes a lot of repeats to be useful. That said, for high/higher intensity workouts I still prefer flat, higher paced intervals or tempo runs. Possibly a bit old school, but I find a couple of benefits: one is that with flat(-ish) intervals or tempo runs terrain does not influence effort; two is it helps me maintain more rapid leg-turnover and the ability to run fast. Whereas the ability to run fast and hard on the flats contributes to my ability to sustain uphill efforts, the reverse is not true – hard uphill efforts do not make me fast for the easier sections of a race.
It seems you have a good hill for the 4 min intervals, but there can be good reasons to not worry about vertical for longer intervals or tempo runs. Even Kilian seems to be working on road speed these days.