Combine rotator in blueprint execution order

I was watching a [video][1]. This video link points to exact time what I wish to ask. In this video the Character’s rotation has been added with ‘combine rotator function’ and with a Yaw value of 22.5.

I don’t understand this. He says that rotation values are from 0 to 180 with sign -/+ so whats the point of adding 22.5 & making 180+22.5 = 202.5?

Can’t we determine if its 0 then north, if 45 degree than North east, if -45 then North West and like that?