ᐅ Light well cover / window well cover

Hello,

I have some general questions about light well covers and hope this is the right place to ask.

What exactly is the purpose of these covers?
Are they mainly to prevent light wells from being "flooded" from above during heavy rain?
My light wells have a hole in the middle, so they should be connected to the drainage system.

The basement windows in my house are old metal ones. Could the cover also help prevent heavy rainwater from pressing against the house wall and finding its way into the basement through the window?

Thanks for your thoughts.

Best regards,
Dimi