All grumpiness aside (ahem), I'm guessing that the reason they want you to
bleed the system in the specified way, and that the bleeder bolt is where it
is, is so that there won't be an air pocket where the fan thermoswitch is.
I'm further guessing that the switch has to be in decent contact with the
coolant to work properly, and it won't if said air pocket is there in the
top of the radiator. The system may be 'self-bleeding', but I really don't
see how an air pocket of any size at the top of the radiator would ever get
bled off.
To add the obligatory useless personal anecdote, I once filled the system
without bleeding it while I was in the midst of one of my transmission
adventures (knowing that I was just going to drain it again soon), and the
led went well up the gauge (3/4) but the radiator fan never came on and the
radiator was hot. In thinking about it later after I bled it properly and it
returned to normal behavior I got the idea about the air bubble interfering
with the thermoswitch.
I'm sure somebody will be happy to correct me if I'm wrong.

Cya,
Robert