I did AppSec for a couple of years just for a change of pace. The friend who worked there said they wanted to strengthen their infosec program in general, which is why they wanted to hire an SWE for AppSec instead of using cyber boot camp grads like they had been. Turned out 90% of infosec is about creating all of the necessary paperwork to protect to company from liability if there's a breach. Actual security issues were ignored most of the time if there wasn't a compliance framework that addressed the vuln directly. We could have tripled the number of people in the department and it wouldn't have made any difference in terms of actual security. Maybe the compliance paperwork would have been submitted a bit sooner.