I use my nakiri more than any other knife. From my perspective, the shape has these advantages:
The curved part of the blade, the transition from the bottom to the front is sharpened just like the bottom edge. The bottom edge gets more abuse with chopping, but that spares the front curve. The front curve remains super sharp for precision draw slicing, vertical cuts on an onion, etc. In other words, chopping doesn't affect the more precise use of the knife, the way it might (depending on your technique) with a gyuto/Western chef knife.
The 90 degree flat part of the front is perfect for turning the knife more vertical and moving product around the board, like a scraper when organizing piles of garlic or ginger for chopping. It's faster and less messy than flipping the knife over to use the spine when you want to scrape and move product around without risk of damaging the sharpened edge.
A nakiri has a lot more vertical surface area than a gyuto or Western chef knife, so when slicing or chopping food, it doesn't climb up over the top of the blade as much. That flat area is also useful for transferring cut product to a bowl, again as a scraper, using a very low angle to avoid damaging the blade edge. I can move a larger pile of sliced or chopped food around with a 165mm nakiri than I can with anything except a much longer gyuto.
Due to the blade height, the blade weight of a nakiri is higher than a gyuto shape of equivalent length. This means that for free-hand, off-board vertical chopping, I can get a nice controlled rhythm with some power (weight) behind it.
Finally, it's really easy to sharpen compared to some other shapes.