I am going back to an Audience of One.....the treasures that we store I believe are kindness, thoughtfulness, grace and uncondtional love. Each day we are given the opportunity to make hundreds of choices, the easy, feel good choices are often rewarded in the earthly realm, the harder intentional choices are invested in the heavenly realm. The truth of the heart motive does need to be investigated and often God directs us in how to handle the situation.
The advantage of this is that the 'interest' pays off in the earthly realm in being closer to God and being blessed. Seeds planted bring harvests.
I think we are uncomfortable with the concepts of rewards in heaven because it is like the parable of the rich fool we would like to just eat , drink and make merry and coast and think that as long as we say Jesus is Lord we will have everything. Their is a judgement.