The hilt of a dagger: the difference between annotating a class @Singleton and providing a function @Singleton

My question is pretty straightforward: what's the difference between the two comments/examples:

Example 1

@Singleton
class MySingletonClass() {}

@Module
@InstallIn(FragmentComponent::class)
abstract class MyFragmentModule {
   @Provides
   fun provideMySingletonClass() = MySingletonClass()
}

Example 2

class MySingletonClass() {}

@Module
@InstallIn(FragmentComponent::class)
abstract class MyFragmentModule {

   @Singleton
   @Provides
   fun provideMySingletonClass() = MySingletonClass()
}

The only difference I know is that the second example gives me the following error:

error: [Dagger/IncompatiblyScopedBindings] FragmentC scoped with @dagger.hilt.android.scopes.FragmentScoped may not reference bindings with different scopes:

Does this mean that the comments in @Singletonexample one are simply ignored?