You use a twist drill bit and only rotary motion when you want to CUT a
hole through a material like wood, steel, plastic, aluminum, etc.
You use the hammer function and a masonry bit to BATTER a hole through
masonry materials like brick, concrete, rock, mortar, etc.
Consequently, a dull masonary drill bit works much better than a dull
twist drill bit cuz there's no cutting involved. It's all a matter of
bashing the material in front of the bit into rubble (that gets augered
out of the hole by the flutes).
If it wuz me, I wouldn't use the hammering function with a keyless chuck
unless you're drilling into masonry with a masonry bit. I have a Hilti
rotary hammer with an SDS chuck, and as a freebee I got a keyless chuck
accessory that could be installed in the SDS chuck for using twist drill
bits up to 1/2 inch in diameter. The owners manual warned me never to
use that keyless chuck accessory when the tool was in hammer mode
because the keyless chuck was press fit together and the pounding action
of the tool could shake it apart. Admittedly, the hammering action of
your cordless drill won't be as strong as a corded rotary hammer, but if
it wuz my cordless drill, I'd play it safe and not use the hammer
function unless you need it (meaning you've got a masonry bit in the
keyless chuck and you're drilling into masonry).
I like pigs.
Dogs look up to us.
Cats look down at us.
Pigs consider us equals.
-----one of Winston Churchill's speech writers