Whilst it is true, you do not NEED alignment pins on camshafts or in this case the nub on the crankshaft gear, putting an engine together without them is dodgy.
It makes life more confusing when changing cam belts, and it wastes the next mechanics time when he wonders why the timing marks are nowhere near alignment eluding to the possibility that the crankshaft pulley vibration damper has slipped between the rubber and metal section. Without the rectangle guide nub there is no reference to TDC using the mark on the pulley
In summary you do not technically need to make the gears align, but if you're going to do a job, why not do it 100% proper
