It is so that users of multiple services can be identified on each portal uniquely. Such as gamer tags or other name spaces they use in a nip-05 implementation. Sometimes the length of existing nip-05 is not suitable internally when using legacy software that is integrated and unique short names (before the @) are useful on the platform.
I have intentions of launching several portals and a few of them would thrive much better this way.
Also, it allows users to search for these verified aliases without it being the primary display on the profile. It is about enabling more use cases that are not easily enabled now.
