Hey Solar, you were a few seconds faster than me...
... exactly, the push buttons from Jung (532-4U), Gira (014700), Berker (503404), Hager (WUE34) cost 10-15 € each, plus normal series rocker switches.
The 6411U-101 is like using a cannonball to shoot sparrows, and on top of the 80 €, you have the same amount again for the control panel, so cost factor 1:10...
The push buttons are to be connected with YJ(ST)Y 2x2x0.6 to an Elsner conservatory control system (24V low voltage, locking occurs in the device) that regulates everything...