With Amberser's current status, a Ninth Circle Spell is of little significance to him.
As long as he continues to amass wealth unceasingly, he can easily cast spells like the Revenge Storm, another Ninth Circle Spell, with 'pay-to-win' tactics. However, acquiring another gift from Talos simply gives Talos an excuse to meddle in his affairs.
But a divine gift does not require the approval of mortals. As long as it doesn't harbor any malicious intent, a deity is unrestricted in how they bestow their power.
When Shael shared knowledge of the Dark Web with Amberser, it only served a locational purpose and couldn't be used to harm Amberser. When Rowetta forcibly advanced Amberser to legendary status, reclaiming the unwanted Power of Destiny, Rowetta didn't leave any traps behind but merely limited the ceiling of Amberser's Destiny Weaving ability.
So Amberser isn't worried that the Thunder Mark on his hand will suddenly reduce him to ashes.
It's just that he can't refuse this gift.
