Goddess Lakshmi is believed to have been born on Phalguna Purnima, the full moon day in the Phalguna month, during the divine event known as Samudra Manthan (the churning of the cosmic ocean).
She is all powerful. So even if Kali is worshipped during Diwali or Dipannita, as we say in Bengal, not only in a mandap or temples but in a few homes too, Ma Lakshmi is no less an important deity.