Actually no, the second half of the video does not show you that, it displays a bar but you don't show how to link the health with the bar and have it update. The bar did not update in the video alongside you decreasing or increasing the health with clicks.
I was not having any issues using integers, it worked fine for me, only when I linked it to NGUI did I need to convert them to a float in order to use them alongside NGUI.