When would you use flex-flow property and what is it good for?

The flex-flow property will save you some time. As it is a shorthand property for flex-direction property and flex-wrap property, you can use it at any time when you would be defining both of these properties in your CSS ruleset.

The flex-flow property is often used for styling navigations and menus or other lists that can items - product cards or application tiles.

The flex-wrap property defines how the flex container items will be wrapped if they don't fit on one line (or column).

Thanks to this property you don't need to write that many characters. And the CSS has smaller footprint which means it can be downloaded faster.

div {
  display: flex;
  flex-flow: column nowrap;
}