Use Office standard of Ctr+Shift+C/V to cut & paste cell style
Many Office apps allow you to select text style with a Ctrl+Shift+C, and paste it with Ctrl+Shift+V. Implementing this in Excel for the Format Painter would eliminate a relatively slow mouse-heavy operation.
Excel already supports this. Simply Ctrl+C to copy the format you want, and then Ctrl+Alt+V, T to paste formatting. (That’s Past Special > Formats)