Without the Option key, it grows as if pinned by its top left corner. Usually, holding down the Option key while resizing a square, for instance, will cause the square to stay in place, and grow out from its center point. But you can’t hold the ⌥ key to pin a resize action to its center. You can ⌘D to deselect, for example, or ⇧⌘I to invert a selection, or use the bracket keys to resize a brush. Like the rest of the app, not all shortcuts are present, but the important ones are here. At least the developers had time to put in some jokes.
I used to work as a designer, and these shortcuts are still baked into my fingers and brain.
Watch any experienced photoshopper at work, and their left hand is as active as the right, pressing key combos like a pianist plays chords. This is one of the most essential parts of Photoshop for serious users. What Photoshop does have is keyboard shortcuts.
