The people from whom I learnt this process and with whom I have done this thousands of times are now on the opposite side and i am lighting these sticks for them as well.
I have always thought that we do that to pay respect, to probably have a connection with the other world while we chant or say things we want to say to our God's or elders but I think it is more than that.
It is act of showing that you care and you miss them and even if you're not putting the insence in front of their pictures; by putting them anywhere you feel you're with them, they are part of you, they are still with you. This clearly means atleast for me now, that I'm not doing anything for them but for my own self, for feeling calm, for showing my own self that i remember and care and miss them.
All these things are for me, aren't they?