Today it is not possible to use alias attributes in Partslink classification.
Alias attributes is a excellent was to show related information on a wtpart. Ex. number of Described by documents. Change management comments... By having it on a wtpart it can be easy distributed to downstream systems.
The use case is to only have this information for some wtparts. And here we for all other attributes can use classification. It would be great if alias attributes also can be used for classifications. Other wtparts may need different alias attributes.
By using alias attribute we can limit the number of customizations.