Comma usage in this particular case

[cc_editor]

Hi to All,
I am learning Punctuation.
I stumbled across this particular text, and I would like to know why a comma was used in that particular instance. Here is the text:

"Whether you're a stay-at-home parent, or a college student with an extra hour between classes, at CloudCrowd, you work on your schedule. Join today, and start turning your idle time into income."

I a would like to know why after "at CloudCrowd" a comma has been used, and whether it is mandatory or not? Can you also explain in more detail that particular grammatical rule for using a comma in that particular case?

Thank you in advance, and looking forward to hearing a answer.

Sincerely, cc_editor

[Rover_KE]

It's redundant, as are the commas after 'parent' and 'today'.

It's an example of promotional material in which the author thinks there should be pauses for effect at those places if the sentence were to be read aloud.

Rover