The Tube map is roughly geographic. Amersham really is North West of London. Waterloo really is South of the river. It doesn't try to preserve the geographic integrity you'd need for say, a walking map but it also isn't willing to just put a station where it would fit best aesthetically despite being completely wrong for geography.
It’s not an aesthetic decision, it’s a practical one juggling space constraints and clarity.
Where I live we have both: the main maps are non-geographic, and that allows them to be placed in several locations including the trains themselves. Geographic maps do exist, but take so much space they are only displayed at certain points in certain stations.
