Angular DI Injection token's type does not match a factory's return value type but service accepts

Question

Why is it possible to provide an injection token of some type but can pass an actual value of a differing type and this be accepted in a service injected with the token?

import { InjectionToken } from '@angular/core';

export const CONFIG = new InjectionToken<string>("SomeToken");

export interface Config {
    environment: 'someEnv' | 'someEnvTwo';
}

export function configurationFactory(): any {
    const configuration = {
        environment: 'someEnv';
    }
    return configuration;
}

@NgModule({
    imports: [...],
    exports: [...],
    providers: [
        {
            provide: CONFIG,
            useFactory: configurationFactory
        }
    ]
})
export class SomeModule { }

@Injectable({
  providedIn: 'root',
})
export class ConfigurationService {
    constructor(@Inject(CONFIG) private config: Config) {
        const environment = config.environment;
    }
}

In this case, the ConfigurationService is injected with the CONFIG token that is of type string but defines the type as Config. In the module it specifies providing the CONFIG token and using a value typed as any but conforms to the Config interface.

Wouldn't the ConfigurationService have a conflict with the token, being specified as type string, not conforming to the Config type in the construction parameter?

Wouldn't the module's provided CONFIG_TOKEN conflict with the factory returning an any object rather than a string?

Referencing the Angular DI Documentation suggests to me that this shouldn't be possible, however this does work.