We had a different kind of tab on our fire department boots. They laced into the boots and looked just like the ones you mention, but they had a zipper down the middle. The reason? That way you could easily unzip your regular boots, kick them off, and then hope into your firefighting gear and firefighting boots. Minimized changing time since we had to be fully changed before hopping on the engine. It might seem like a short amount of time to unlace a boot, but in a fire those seconds are precious.