It still provides some of the same ergonomics. You can put away the mental cheat-sheet ("1: gold, 2: silver...."). Your IDE can find all uses of BookTypeId.Gold(), rather than textual occurrences of "1". Etc.
The static quality of enums is only one of their features, and sometimes a hindrance, and it good to have other options.
The static quality of enums is only one of their features, and sometimes a hindrance, and it good to have other options.