I saw a similar but different variation involving a low-use system. Imagine it was a system for detectives to track complex murder* investigations. They only n

I saw a similar but different variation involving a low-use system. Imagine it was a system for detectives to track complex murder* investigations. They only need to conduct approx 10 such investigations per year, but quality/correctness is crucial. The full end to end tests are performed thousands and thousands of time per year, and if they are slow the entire development effort is slow. So you end up needing to make the whole system performant - even though end users aren’t experiencing the pain, devs/QA are. (* this is not the actual domain, but similar rarity + criticality)