Why the player cannot be loaded even when the keyboard control is active?

Question

Why the player cannot be loaded even when the keyboard control is active?

Answer

Even when the player control is active, video play cannot be initiated by  Tab + Enter and a manual click on Play overlay is required. 

This behavior is due to the enablement of Lazy Loading.

When lazy loading is enabled, a dummy player is shown which doesn't support Keyboard Control. Manual clicking on the Play button is required when Lazy Loading is enabled.