This odd piece oddly is almost a rook worth in the endgame.
It still has the can-mate property, except for the rare case
that the bared king is in the secure corner (If the odd piece
is on a1, the secure corner is a8). In the most cases it
can block the secure corner and the bared king is driven by zugzwang
towards a mate. The secure spots left by the odd piece are all
single fields without secure neighbours -- thus a bare king must leave
them.
--J'org Knappen