I checked out John Ward's great Youtube trilogy on Arc Fault Detection Devices
(quote JW:
'Arc Fault Deception Devices' )
and there is no way I would have a 3 way 'all in one' combo wasting 3 Din rail spaces,
eventually nuisance tripping, or not at all, once the unit ages a bit and or exposed to hot/cold/dust/moisture snafus
If they become compulsory here, I'll opt for a larger main board or addon if necessary with separate module AFDDs or AFCDs,
so I can test and get them swapped out if they are duds/placebos,
and leave the working MCB and RCDs or RCBO combos alone to do their job.
..and save serious dollars not having to pay out on clapped 3 space 'three in ones'