My bad.
Be careful with Application.Visible= False; if your code crashes or needs you to respond to a dialogue box, you'll be left with a hidden instance of Excel running in the background, with open workbooks and you'll need to use Task Manager to kill it, losing any unsaved work.
In any event, Application.Visible= False is unlikely to make a material difference to the execution speed; it may actually slow it down slightly, as Windows has to hide Excel and repaint the screen with whatever you'd see if you minimised the Excel window,