Many of the new generation have full PFD on SBY electrics, and it would take multiple failures of electrics & screens to achieve the small SBY instruments only, but why not use it as an educating exercise to improve feel/touch & scan
Agree. In fact, on all ILS I advise the PF to bring up the ILS up on the standby ADI.
It gives the pilot practice at switching his gaze solely from the PFD ILS display to a few inches across the instrument panel to the standby ADI where the needles may be slightly different and the nose attitude scale is very small.
Depending on the design of the instrument, the needles of the standby ADI can partially hide the horizon bar making it difficult to see the real nose attitude. Having the ILS switched on the standby ADI during every ILS, gives the pilot (left or right seat) efficient scanning practice at using the standby ADI for real if the situation ever demands it.