Pointless signs - New Cross

This from Pedantic of Purley...

This sign is approximately 60 yards (less than a train length) from the buffer stop at the London Overground bay platform at New Cross.


You cannot see it if the train is leaving the platform because the train itself obscures the sign and on its inward journey the train is traveling at walking pace due to TPWS slow speed control when entering terminus platforms.

If it is logical to put this sign up then presumably logically this ought to apply to all terminus platforms and these signs should decorate the London termini stations?

Needless to say there is no such notice by the track at platform B which is a through line and does have trains passing either way at a much higher speed.