Give us this day our daily bread was part of the prayer Jesus used when illustrating how we should pray. He did not tell us to pray, give us this month our monthly bread. He did not tell us, give us this year our yearly bread. He told us to pray daily for that days need.
We might think that to God our daily needs might seem trivial, but our God wants to be the God you depend on each and every day. Not just once a year or once a month.
The statement also implies that we should pray daily.
God wants to be our everyday Lord. Not just our God when we are desperate.
God give us what we need this day!