You are right - there are also 3 clicks in K1 (I mixed it up due to different order: In K1 you have to select the kind of waypoint before placing the crosshair).
But nevertheless needing only 2 clicks in K3 would improve / speed up:
- after long tap on map crosshair appears, and in parallel the 4 buttons (Start, ViaPoint, ShapingPoint, Destination) are shown in left panel
- then crosshair has to be placed and one of the 4 buttons can be tapped
There was (and perhaps still is, but I can not find it) a mode on the website, where I just had to do 1 click on a map point, and route was extended with that point as new destination - I really appreciated that, when I did the routing myself (via a paper map) and wanted to create an identical Kurviger route.
Of course 2 clicks are necessary, if the possibility to select waypoint type individually is given - as far as I remember even the waypoint type (Via or Shaping) of previous destination when extending via 1 click method could / can be configured.