In the later apple][/C64/etc era most of the color composite monitors also had that B&W switch built in. That way you flip it when editing text/etc vs playing games. The one I had also had a green screen button, which turned it into a green/black monitor.
The 8-Bit guy did a great piece on CGA that goes into detail about how old developers abused the fuzzy smeary nature of composite signals to output somewhat decent graphics. The tricks however didn't work when people upgraded to proper monitors and as a result a lot of CGA games look much worse today than they did on the intended equipment of the day.
