Arth-Goldau in Switzerland has, courtesy of its role as the the interchange point for the Basel and Zürich arms of the Gotthard line, a far better service of express trains, including international services, than the pair of small towns it is named for would normally ‘deserve’.
The problem here is that - the introductory question was "Which railway stations outside of the UK have a far more important role (in any practical way) than might be expected? "
But Arth Goldau's importance (like Crewe) is not 'unexpected'
Similarly, this applies to any of the main railway junctions situated in 'remote' locations across Europe which are catapulted to 'importance' by the nature of their position on the railway network.
An example that comes to mind from the old days was Linares-Baeza in Spain
There is another candidate in Switzerland: Sagliains
For those who don't know, when the RhB Vereina Tunnel (Klosters - Engadin valley) was designed, the best way to enable connections onto existing routes at the south end (Engadin aka Inn valley) was to create a station between Susch and Lavin on the Samedan - Scuol Tarasp line, but there is no settlement of Sagliains, it is a name taken from a geographical feature. Thus the station has no exit to the surrounding land, so you can not leave the platform, only change trains there.
The only exception is that you can drive there by car to board the tunnel car shuttle.