I don’t see any other advantages of grouping stations then uncluttering the screen. I used to group stations often, but now I don’t anymore. Leaving stations ungrouped has to me two minor advantages:
- less (minor) glitches during modification works of lines (mentioned above)
- a more clear report about waiting passengers or cargo: per line a status, in stead of one global status.
The fact that two opposite stops are grouped by default, is a gain (again in the screen clutter department).