From TIBCO Spotfire 7.8 onwards you have the option to enable and set the Public address URL from the TIBCO Spotfire Configuration tool as well.
We can still set the Public endpoint/address from the command line as mentioned in the below Knowledge Article:

How to update the Web Player URL used while generating absolute URLs when saving analysis files as a library item with the Analyst Client.

When making a configuration change using the TIBCO Spotfire Configuration Tool remotely, you would not be able to set the Public address and would see the warning message like:

It is a possibility that a user is using the TIBCO Spotfire Configuration tool remotely by following the steps mentioned in the below documentation:

Running the configuration tool on a local computer

When running the uiconfig.bat remotely by connecting to your Spotfire Server you will need to export the currently used configuration by doing "Export configuration from database" and set your public address by adding the below setting in the configuration file:

 <public-address>     <enabled>true</enabled>     <url>http://serverAlias</url> </public-address>

Save the configuration.xml after making the change and import it back using "Load configuration from file" and use the file where you made the above change.

You will need to restart your Spotfire Server to have this change take effect.

However, a user not running the TIBCO Spotfire Configuration Tool remotely or having access to the machine on which the Spotfire Server is installed can still make a change directly from the uiconfig.bat file by accessing it from Installed Directory\tibco\tss\7.12.0\tomcat\bin\uiconfig.bat 

Setting the Public address URL when running the TIBCO Spotfire Configuration Tool remotely.

How to update the Web Player URL used while generating absolute URLs when saving analysis files as a library item with the Analyst Client: https://support.tibco.com/s/article/Tibco-KnowledgeArticle-Article-48198

set-public-address: https://docs.tibco.com/pub/spotfire_server/7.9.0/doc/html/TIB_sfire_server_tsas_admin_help/GUID-1168B883-EFAE-4F42-A652-45FF2A7CC143.html

Running the configuration tool on a local computer: https://docs.tibco.com/pub/spotfire_server/7.12.0/doc/html/TIB_sfire_server_tsas_admin_help/GUID-64C519C3-4EF6-4285-A2CF-F4E319682C41.html