Alias Dimension Property in V9.1

You should not need any rule to use aliases. The point of aliases is not to display; they are meant to be used for references, so that you can use A#MyAccount or A#MyAliasAccount and the cube view will show MyAccount either way.

They are mostly expected to be used incrementally, as metadata evolves, to avoid artefacts from breaking when members are renamed. Fromhttps://documentation.onestream.com/docs/Content/Design%20and%20Reference/Cube/Configurable%20Dimensions.html (the bold is mine):

Aliases are optional names that you can use as alternative ways to reference members from areas such as Member Filters, Cube Views, or Business Rules. This enables you to use additional, readable names for dimension members in new or existing solutions, without disrupting existing solutions that reference the main dimension member names. For example, you can add the original dimension member name as an alias before renaming the dimension member name to ensure existing solutions referencing the dimension member do not break after the name change. Multiple aliases can also be added to the same dimension member through a comma-delimited list.

Note that this property should not be confused with what the documentation calls "https://documentation.onestream.com/docs/Content/Design%20and%20Reference/Presentation/Alias%20Member%20Descriptions.html"; those are culture-specific descriptions that will only be displayed when the user is configured with a different Culture in the Security page, or when you force a Cube View to display with a specific Culture.