So instead of someone in a warm tower/control room with all manner of reference manuals on a desk which they can spread them out and nothing else pressing and they only have to do it once for any given change in circumstances. And we can presume well rested and have multiple people to check it.
They want to move it to, passing the buck to two people working it out while flying an aircraft and setting up for a landing in crap conditions.
Work load includes flying the aircraft, monitoring the aircraft, briefing the approach, setting up for possible divert with not alot of fuel to spare. They may be at the end of a 12 hour day and in the middle of the night according to thier body clock.
Then they have to find the reference card work it out and then figure out what this actually means for there planned approach. And then repeat if it changes half way through the approach while doing all the other good stuff like checklists and flying the plane etc.
And of course every aircraft is going to have to do it. How many an hour with the potential to get it wrong is that?
Then you will get all the none locals some of which only operate into Europe maybe 1-10 times a year who won't be current and won't have a clue what it means.
What a cracking idea, really going to improve flight safety that little gem.