AtD translation: perils of extravagance

[Mike Jing]

P359.1-7 . . . Reef need act as no more than bunco-steerer, all the
research chores and assumptions of risk to be borne by Archie as principal
party, “thankless tasks, all of them, but no risk, no reward, ain’t that
how it goes?”
       “Ever thus in the world of affairs,” Reef agreed, trying to look
just quizzical enough to suggest the perils of extravagance, yet not enough
to offer provocation—these double-domes being in Reef’s experience never
quite as retiring as they looked, some of them damned touchy, as a matter
of fact.

What does "perils of extravagance" refer to here?