Pushing each of this switches toggles the respective computer on or off, and triggers the whole standard power-on self-test, when going back online. There are only subtle differences to the hard way of removing power from the computer by breaking the circuit.
Actually, the differences of a circuit breaker hard reset of the FACs are not so subtle.
Doing a Push Button (those seen in your picture) reset of a FAC in flight is allowed by the flight crew in flight for one purpose only; clearing / resetting a YAW DAMPER FAULT 1 or 2. It is detailed in the computer reset table of the QRH. They are to be done on only the affected FAC, also, never both together.
Reset via the CBs is restricted to ground only, in the same table, and is for attempting to clear a WINDSHEAR DETECTION FAULT or a REACTIVE WINDSHEAR DETECTION FAULT.
If it is true that the commander "got out of his seat" to reset the FAC via CBs, then he was going for FAC 2, as FAC 1 CBs are on 49VU, the O/H panel and easily within his reach from his seat (unfortunately, your picture does not go far enough back to see them). FAC 2 CBs are on 121VU, behind the F/O.
Resetting by PB affects only the rudder channels of the FAC (rudder damper, trim, and travel limit). All flight envelope computations done by the FAC are left unaffected by this reset.
Resetting via CB, on the other hand, takes off line all flight envelope computations for that FAC, and is an extremely dangerous - not to mention prohibited - practice in flight.
Baffling; there is absolutely no reason whatsoever to try and do a CB reset of a FAC in flight.
Unless, of course, the moral of the story is;
Never say FAC OFF to your companion on the flight deck in an A320, no matter what mood you are in; he might take you quite literally.
