What does menu blocks "Block title as link" option do?
For me it doesn't show the menu name, but the link to the parent menu item of the block. IE with a menu hierarchy like this:

&lt;Main Menu&gt;
-- a
---- b
------ c
------ d
------ e
-- f
-- g


If the block looks like this:

Title
c
d
e


Then having the block title as link makes the title a link to menu item b.