A company wouldn't waste time going through the process if it didn't find it valuable. Being honest during your exit interview will help the organization address inefficiencies and any problems that senior management needs to notice.
You always want to be able to show your employer what you have been working on. Even if it's slow, you can still be productive.
Compensation is not about how hard somebody works. Employers compensate employees based on their positive contributions to the company and what they achieve for the organization.