Can this card remove from play itself when it is being sent to the graveyard since it says "any card sent to the graveyard"
or does it mean only when it is face up and currently on the field?

only when face up n currently on the field

Banisher of the Radiance follows the same rules as Banisher of Light.



When "Banisher of the Light" is destroyed it will be sent to the Graveyard. If "Banisher of the Light" and other monsters are destroyed simultaneously all monsters are sent to the Graveyard.


...it doesn't matter if it's face-up or face-down, it will be sent to the Graveyard unless another effect makes it so like a 2nd face-up Banisher of the Light/Radiance, Macro Cosmos, Dimensional Fissure, etc.