1. Many nonmember spouses are happy to be listed with their member spouse on ward directories. For example, in our ward there is a great man who is very active in the scouting program, is happy to have people contact him (encourages this), but just happens not to be a member (yet!

2. When a person is excommunicated, they disappear from membership lists, which is such an odd thing that it makes people wonder. In MLS we can fix that by adding them back in as a nonmember spouse so that on any ward directories that may be broadly used, they will appear just like they always did. But on the LUWS, the member spouse will suddenly be listed alone, which may raise questions.
Now I know that there are issues about how we could authenticate such people for logging in to the site, since that currently requires a member record number, but that's not really a requirement. The majority of the members of our stake can't login (because they haven't bothered to register), but they are still listed on the site. However, if we could figure out a way to give them access (perhaps piggybacking on their member spouse's authentication), that would be nice.