Perhaps it allows us to survive loss and to (a bit indirectly) deal with the fact that we are all mortal/temporary, to be 'lost' in time...
I was taught not to grieve---and so loss becomes a long, ambiguous process and I want to just cry and grieve and wail in a "normal" way, get it OUT,
but ... depression moves in after I go about dealing with everything as if I am 'fine'...