If the system didn't come up with any good plan to store the 30000 units of God Energy, Leo had already planned what to do with such a huge amount of energy.
'With 30,000 units of God Energy, I can just upgrade all my new Tamer's Spaces to Gold Grade or help any two of the three beasts i.e., Howler, Frosty and Phoenix become Diamond Grade Beasts.'
After the battle, Leo gained 50 new talents which means, he had awakened 50 new Tamer's Spaces.
To upgrade these 50 new talents to Gold Grade, Leo only needs to spend 5500 units of God Energy.
With the remaining units of God Energy, Leo could easily help any two of his Purple Grade Beasts become Diamond Grade Beasts.
Even though it was not a bad choice, Leo didn't want to spend all his God Energy right away because, in the future, he would be fighting more battles alone with his beasts.
At that time, he could gain another huge amount of God Energy which he could spend on himself and his beasts to upgrade his strength.