Yes they are because He even gave an example of the poor widow who had to put in the treasury all that she owned. They are the most valuable as they become fully committed to whatever they might be facing rather than the rich who gives in order to be realised by others that they've got.

Surely, they are very valuable because we are all created by God. Has he said I created you with my own image. So we have to open our hands to sinners and non-believers to change their behaviour for bad to good, to become one. Also God, Jesus said humble yourself and I will lift up.