Thinking about it, there are probably a few reasons i prefer chapattis:
like your friend. i usually find naans to be more filling leaving less room for the main dish.
chapattis are usually thinner so i find the ratio of bread to meat to be just right in each bite.
flavour doesn't detract from the curry
more malleable and good for scooping *as mentioned).
however i suspect the real reason is that chapattis were what i was introduced to first, as a lad, in restaurants during the early 80s.
Don't get me wrong, i've had plenty of nice naans but given the choice i just prefer the simplicity of flavour and texture of a freshly made chapatti.

Can't see any chapatti recipes (my bread of choice), so i'll post the one i use.

makes 1 chapatti

ingredients:
2 heaped atta (chapatti flour).
if no chapatti flour use: 1 heaped tablespoon plain flour + 1 heaped tablespoon wholemeal flour
salt
water

instructions:
-sieve flour into bowl (usually don't bother with the sieving)
-add pinch of salt
-add enough water  & mix so not sticky but will from solid ball
- kneed for a few mins
- leave for at least 30 min
-if making more than 1 chap separate into ping pong size balls
-roll out to desired size (dinner plate?)

-get (preferably non-stick) frying pan as hot as possible.
-dry cook chapatti both sides
should take less than 2min.