Why by some minyanim do the Kohanim stand on a carpet/rug by Bircas Kohanim?
Answer:
The reason for this is that in principle, the Kohanim should be raised on a platform (the duchan), from where they bless the people.
Where there is no platform, the rug helps to raise them a little, which is better than nothing, though still non-ideal.
Best wishes.
