Difference between DisposableEffect and DefaultLifecycleObserver

CustomClass.kt

class CustomClass(
    private val text: String,
    private val lifecycleOwner: LifecycleOwner
): DefaultLifecycleObserver {

    init {
        lifecycleOwner.lifecycle.addObserver(this)
    }

    override fun onCreate(owner: LifecycleOwner) {
        super.onCreate(owner)
        Log.e("CustomClass", "$text -- onCreate")
    }

    override fun onStart(owner: LifecycleOwner) {
        super.onStart(owner)
        Log.e("CustomClass", "$text -- onStart")
    }

    override fun onResume(owner: LifecycleOwner) {
        super.onResume(owner)
        Log.e("CustomClass", "$text -- onResume")
    }

    override fun onPause(owner: LifecycleOwner) {
        super.onPause(owner)
        Log.e("CustomClass", "$text -- onPause")
    }

    override fun onStop(owner: LifecycleOwner) {
        super.onStop(owner)
        Log.e("CustomClass", "$text -- onStop")
    }

    override fun onDestroy(owner: LifecycleOwner) {
        super.onDestroy(owner)
        Log.e("CustomClass", "$text -- onDestroy")
        lifecycleOwner.lifecycle.removeObserver(this)
    }

    fun release() {
        lifecycleOwner.lifecycle.removeObserver(this)
    }
}

MainActivity.kt

class MainActivity : ComponentActivity() {
    fun generateRandomString() = java.util.UUID.randomUUID().toString().substringBefore("-")

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContent {
            MyTheme {
                var text by remember { mutableStateOf(generateRandomString()) }
                Surface(
                    modifier = Modifier.fillMaxSize(),
                    color = MaterialTheme.colors.background
                ) {
                    Column(horizontalAlignment = Alignment.CenterHorizontally) {
                        RandomText(text = text)
                        Button(onClick = { text = generateRandomString() }) {
                            Text(text = "Change text")
                        }
                    }
                }
            }
        }
    }
}

RandomText

// When changing to a new text, onPause, onStop, onDestroy are not called
// If c?.release() is commented and you've tapped the button a few time,
// when putting the app in background all the CustomClass are entering onPause, onStop

@Composable
fun RandomText(text: String) {
    val lifecycleOwner = LocalLifecycleOwner.current
    var c: CustomClass? = null
    Text(text)
    DisposableEffect(text, lifecycleOwner) {
        c = CustomClass(text, lifecycleOwner)
        Log.e("RandomText-Composable", "$text -- in DisposableEffect")
        onDispose {
            c?.release()
            c = null
            Log.e("RandomText-Composable", "$text -- in onDispose")
        }
    }
}