I believe that separate token is this (at least, this is how I understand it, but I've been known to be wrong):

Say that Vugtis creates a game on the Invennium platform. To support that game, he creates VugCoin and VugTime, and VugUSD. Vugcoin would then be airdropped to SPS holders.

So each game has its own tokens built on the GLS platform, and SPS holders are airdropped them.

It's not a new token for Splinterlands but a new utility for SPS.