Homemade Wunderlust made the recommendation that an umbrella is or can be an important piece of kit. The idea being less about the expensive solar reflective umbrellas and more about creating a space to eat or drink in piece.
It offers some shade, yes
It offers some respite from the rain, yes
When combined with a net tent you may be free from bugs, yes
When setting a tarp it can enclose one end or your head, yes