While drawing a major event polygon (specific area) should you click near a hazard the polygon drawing stops and you need to start from scratch. Polygons are complex and having to start from scratch is time consuming and frustrating. Drawing other polygons such as Place area or Map Note allows you to continue to draw a polygon.
Hazards are increasing particularly with traffic lights and this issue frequently occurs. You shouldn't need to turn of map layers to simply draw an event polygon.

Video here of showing behaviour when drawing a event polygon vs map note or area place.

https://drive.google.com/file/d/1ak6eEfnMFikptYZuMW-W9EMPvdWhLqG0/view?usp=drive_link