Why to choose Arrow Drippers

[ZandraJoi]

I have come up with this question in my mind why the arrow drippers are made and what are its benfit for plants?
I do not understanding how does this is very useful products for watering? Any advice really appreciated in this.
take a look at this video of Double arrow dripper

Some people like them as they can put them right where they would want the water to flow to. It looks like you put it deeper in the soil so it can get to the roots better than a dripper that just waters the top layer of the soil.