Understanding `andThen` vs `flatMap` in TypeScript Effects

Hi, I have played with this difference

andThen

andThen

and

flatMap

flatMap

const program1 = pipe(O.none(), Effect.andThen(() => O.some(2))
// vs 
const program2 = pipe(O.some(1), Effect.flatMap(() => O.some(2)))

const program1 = pipe(O.none(), Effect.andThen(() => O.some(2))
// vs 
const program2 = pipe(O.some(1), Effect.flatMap(() => O.some(2)))

from my understanding is that both behave the same, only the minor difference is that

andThen

andThen

can handle both:

andThen(() => O.some(2))

andThen(() => O.some(2))

and

andThen(O.some(2))

andThen(O.some(2))

but for

flatMap

flatMap

can only handle

flatMap(() => O.some(2))

flatMap(() => O.some(2))

are there any others i might have missed?