Hello Dominik,
Yes, people with geodesy and cadastral survey background insist on that y/x order. I never remember the reason, but it's something related to the spheric trigonometry and geodetic conventions.
But since 1938 (I don't remember the exact date), civilians also use the infamous military coordinates, where the eastings values are always (450'000 to 900'000) bigger than the northings (50'000 to 350'000) values, so no confusion is posible. Prior to that, the origin was (unsurprisingly) Bern, with coordinates 0,0
In the LV95 system, x and y were replaced by northing and easting, but again no mixing is possible (within Switzerland though)
Regards,
Marc