Severe Turbulence is a crew killer, as demonstrated by the statistics. I've lost count of how many times I've walked into a galley in smooth air and had to move the securing latches on carts and cannisters that are not being used to a position where they can do their job. When the severe stuff happens, there probably won't be time to secure the galley and carts and cannisters will move around rapidly, crushing and lacerating on the way.
I write from the perspective of somebody who watched one of their crew thrown from one side of the fuselage to the other, where they fractured their arm on the door handle, and as somebody who has had to twice crawl along the aisle to keep low while trying to reach my jumpseat.