You can only select one element at a time in the Bricks canvas at the moment. So, imagine I create a grid of cards and fill out all the content details in each card, only to realize that I forgot to add something like an icon or a modifier class.
Without multi-select, I have to select each individual card one by one and paste the element in or apply the class. Then, I have to select the next instance and repeat the process. And again. And again. And forever for however many instances exist.
With multi-select, I could select every card at once and apply the missing class or paste the missing icon. Or I could delete a class from all instances at once. Or any number of other helpful “bulk” actions, like “wrap with div/block” (giving us the ability to quickly group associated elements together).
Drag-and-drop also comes into play here. The ability to multi-select elements and then drag them to a new area on the page is tremendously helpful from a workflow efficiency perspective. It can also reduce the number of grouping wrappers that might be needed.
Ideally, multi-select would work both in the canvas and the structure panel so I can multi-select from either area.
Both forms of multi-select would work, of course: shift + click as well as cmd + click. The expected behavior would be the same as in any operating or file system.