구글지도 사용하기 중 코드 질문..

아래 코드에서 _HomeScreenState 클래스에서 appBar와 Body를 나누신 후에, 코드 정리중

appBar는 함수로, _CustomGoogleMap과 ChooCheckButton은 위젯으로 분리하여 만들어주셨는데, 그 이유가 뭔가요? appBar는 위젯으로 관리를 하면 안되는건가요?

import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';

class HomeScreen extends StatefulWidget {
  const HomeScreen({super.key});

  @override
  State<HomeScreen> createState() => _HomeScreenState();
}

class _HomeScreenState extends State<HomeScreen> {
  static final LatLng companyLatLng = LatLng(37.5233273, 126.921252);
  static final CameraPosition initialPosition = CameraPosition(
    target: companyLatLng,
    zoom: 15,
  );

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: renderAppbar(),
      body: Column(
        children: [
          _CustomGoogleMap(initialPosition: initialPosition),
          _ChoolCheckButton(),
        ],
      ),
    );
  }

  AppBar renderAppbar() {
    return AppBar(
      title: Text(
        '오늘도 출근',
        style: TextStyle(
          color: Colors.blue,
          fontWeight: FontWeight.w700,
        ),
      ),
      backgroundColor: Colors.white,
    );
  }
}

class _CustomGoogleMap extends StatelessWidget {
  final CameraPosition initialPosition;

  const _CustomGoogleMap({
    required this.initialPosition,
    Key? key,
  }) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Expanded(
      flex: 5,
      child: GoogleMap(
        mapType: MapType.normal,
        initialCameraPosition: initialPosition,
      ),
    );
  }
}

class _ChoolCheckButton extends StatelessWidget {
  const _ChoolCheckButton({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return Expanded(
      child: Text(
        '출근',
      ),
    );
  }
}