This story is commonly mis-applied as a "tithing" story (a commandment). How can one justify sacrificing necessities of life (food, shelter, clothing) in order to construct and maintain buildings for the purpose of benefitting the dead or well fed?
The widow's mite could be better described as a "fast offering".
I think it is more about a higher law of giving/sacrificing without being compelled. Giving not so much out of duty, but a trust/love for the Lawgiver or those the donation may benefit - that are truly in need.