Crab surely depends how the BUG aural warnings are designed in the individual aircraft. In the EC225 with the latest VMS software, the DA/MDA bug is set to the relevant value on the approach chart and DH bug is set some margin below the relevant DH/MDH on the chart. This provides visual warnings when the minima is achieved (via the DA/MDA bug) and an aural warning at the margin chosen below the minima, at the height set on the DH/MDH bug.
The logic is the crew can converse at minima without the aural warning sounding at the same time. However if they miss the achievement of minima through some distraction the aural warning will alert them that they are BELOW the minima. Of course if the approach continues normally the aural will sound anyway so its not perfect but better than average I would say.