If you have a pick list of 10 items and you mark four of them, then (with an SSAS source) it will use an exclusive filter (EXCEPT()) to just exclude the six you did not mark. But in an SSAS case you'd want to do an inclusive filter to just select the four you wanted in the filter. It prevents the use of DefaultMembers in the SSAS cube. If you have 300,000 items in a pick list you may want to be able to just say "exclude this one item" instead of selecting the other 299,999. Instead of picking from a list I should be able to choose include or exclude based upon my requirements.