It reduces costs and increases productivity especially for fixed-price/outcome-based projects.
Pro-active error detection leads to less rework, on-time delivery.
Compensate for lack of skills at bottom of skill pyramid.
Reduce attrition impact codifying audit rules.

Reduction in cost to business due to defects
300 critical issues (+1600 moderate priority issues) detected
Even if only 20% (60 issues) are encountered in production
Cost per production defect is at least $5000
Savings = 60 x $5000 = $300,000
Savings in cost of defect identification
A test engineer detects 1 defect per day on average
Cost per day = $20,000 per year/250 days = $80 per day
300 critical errors detected: savings = $24,000
Savings in cost of code review
A developer takes on average 1 day to review 1000 LOC
Cost per day = $20,000 per year/250 days = $80 per day
200,000 LOC reviewed: savings = $16,000
Total savings = $340,000
Savings per 100,000 LOC = $170,000
Risk mitigation
Pro-actively detect and remove critical errors missed by testing
Especially in legacy code, after attrition
Enhanced developer skillset
Audit feedback and learning for engineers
Adoption of industry best practices
Testing alone is not sufficient
Audit + testing provides best solution
Better vendor management
Audit ensures higher quality of delivered code