If you wanted to craft am inventory full of gold nuggets into ingots, for example, shift-clicking an item from the vanilla crafting book automatically puts as much as you can craft into the crafting table. I think it would be a nice quality of life function if JEI could do the same thing in the search menu or bookmarked items section, as currently you'd have to click the item, find the recipe you're looking for, then shift-click plus.