Hello Mauro,
concerning your questions
Other question that came up was "why is it so important for that
node
to be unconnected with the railway track?"
Can someone help me to know exactly why it's better tagging a
"railway=station" with a node only?
I prefer the passengers view of a station or halt. If we will meet "at
the station" where are you expecting to find me? This is the position, I
usualy use for placing the railway=station node, definitly not on a
track. The track carries nodes like public_transport=stop_position.
Putting 'station' on a building or even a larger area leaves it to the
renderer or any other data consumer to guess the center of the station
from passenges view.
Cheers
Nzara