The main utility of being able to know what the chat triggers are is if you want to display to clients how to type commands.
e.g. Welcome to the server! Type !rules for the server rules.

Or for chat processing, I guess.

Although I've never even encountered a server that has changed the chat triggers--so it's usually fine for plugins to just assume that ! and / are correct--it's still allowed to be changed, and currently the only way to get the actual chat triggers is processing the core.cfg file manually.

Tested with the following code:

#include <sourcemod>

public void OnPluginStart()
{
    char buffer[32];
    int written;
    
    written = GetPublicChatTriggers(buffer, sizeof(buffer));
    PrintToServer("Public Triggers: '%s', written=%i", buffer, written);
    
    written = GetSilentChatTriggers(buffer, sizeof(buffer));
    PrintToServer("Silent Triggers: '%s', written=%i", buffer, written);
    
    // Outputs
    // Public Triggers: '!', written=1
    // Silent Triggers: '/', written=1

}