[Elecraft] Advantage of KBPF3 in K3?

[Jeff Cathrow]

 No response to my earlier question about the usefulness of the KBPF3 posed last week so here goes again;  
 
if one already has an AM filter in one of the K3's slots what does one need a KBPF3 for (in terms of general coverage SWLing)?
 
Does it allow band selection of the popular SWBC bands in addition to the ham bands?
 
Still curious.
 
73, Jeff, NH7RO
K-Line proud assembler/owner since 2011