Why do the NestJS decorators like @BooleanFlag return Observables?

[benkenawell]

The value doesn't update over time, does it? What's the value in wrapping it in an Observable? Why not return the promise directly from client.getBooleanDetails?

[benkenawell]

Fastify doesn't seem to unwrap Observables returned from controllers like Express will, so some of the examples on the site don't work the way they show.