The word may have fallen out of favor, but I think the concept of “good, but not required” is alive and well in almost all folk morality. It’s troublesome for (non-divine-command) philosophical approaches because you have to justify the line between ‘obligation’ and ‘supererogation’ somehow. I suspect the concept might sort of map onto a contractarian approach by defining ‘obligatory’ as ‘society should sanction you for not doing it’ and ‘supererogatory’ as ‘good but not obligatory’, though that raises as many questions as it answers.
The word may have fallen out of favor, but I think the concept of “good, but not required” is alive and well in almost all folk morality. It’s troublesome for (non-divine-command) philosophical approaches because you have to justify the line between ‘obligation’ and ‘supererogation’ somehow. I suspect the concept might sort of map onto a contractarian approach by defining ‘obligatory’ as ‘society should sanction you for not doing it’ and ‘supererogatory’ as ‘good but not obligatory’, though that raises as many questions as it answers.