The 159 front wheel bearings are integrated in the hub and you can't take out the bearing non destructively (Maybe SKF can do it, but I don't think that ordinary people can
So the bearing is seated and aligned in to the hub in the factory long before your car sees it.
If the drive shaft is not aligned with the hub then the hub will not want to go onto the drive shaft in the first place.
So the only sensible explanation is that the this procedure somehow ensures that the hub gets properly seated onto the drive shaft.
But in that case I would expect something like:
1. Tighten the nut to some torque
2. Tighten the nut through some angle
3. While doing this, ensure that the torque falls in some range (because if it doesn't then the hub is probably having difficulty going on to the driveshaft)
I have asked two friends with a degree in mechanical engineering who had no clue what all that procedure does. Also I asked one car mechanic who repairs high end Japanese cars and he said that he never done something like this and he also never heard that something similar needed to be done..
At the end of the day a lot of mechanics just hammer on the nut with their favourite impact wrench when taking hubs of driveshafts and when putting them back together even if they are not even remotely supposed to do that since the bearing certainly does not like the hammering action.... but who am I to judge...
Anyway... there is no problem in following the procedure right down to the last letter. Even if it had extra steps:
2.1. Have a coffee
4.1. Spin yourself around for 360 degrees
But the point is that eLearn being the official Alfa Romeo documentation, someone must have written that down for a reason and I don't like to blindly follow such instructions with no clue what each step does, but instead I like to learn new things from the Italian car masters
I am tempted to agree with Hoggins though... I guess that if you ask AR dealers how many warranty replacements they had for 159 front wheel hubs that the answer will be 0 and all failures will get attributed to "Incorrect assembly procedure"