Besides learning more techniques to improve his defense or movement speed, Shane couldn't do much to increase his combat prowess.
Only purchasing even better equipment than he currently had or choosing his occupation would change something.
Without knowing what his next [Mythic] mission would be, Shane didn't want to splurge and avoid being short on funds.
For that to happen, his next move would be to prioritize his capabilities to handle his acquired funds.
After his first mission demanded him to acquire funds in a short time, the system might demand that he would do something similar.
As such, Shane was reluctant to utilize a large chunk of his funds after purchasing the world seed.
With more than 30,000 Gold coins, he was confident to solve the [Mythic] mission to receive the permission to purchase the [Tier-1 (Mythic)] body refining technique.