those black screen tarps...

are those needed?

whats the pros'cons of them vs giving plants direct sun light?

Some plants grow better in cooler weather, with less direct sun. If you wanted to grow those cool weather plants in hot sunny locations, you would use a screen. Like growing pumpkins in Hawaii, or sugar peas in So. Cal.

The Cannabis plant can handle the full sun, so its not really needed unless you want to block view from above, or if you are growing in a hot location, like growing an afgani in southern Arizona.

sweet someone posted this
um. Yeah I wasn't sure either, I was thinking of making a little 1x1x3 box with a black screen all around it
but i'm not sure what would be the best screen to use, to do so?
does anyone here know?

If your hiding from the DEA then yes.