Bean등록 부분이 이해가 안됩니다.

첫번쨰로 수동으로 등록한다고 했을때

package hello.core.config;

import hello.core.discount.DiscountPolicy;
import hello.core.discount.impl.FixDiscountPolicy;
import hello.core.discount.impl.RateDiscountPoilcy;
import hello.core.member.repository.MemberReposotory;
import hello.core.member.repository.impl.MemoryMemberRepository;
import hello.core.member.service.MemberService;
import hello.core.member.service.impl.MemberServiceImpl;
import hello.core.order.service.OrderService;
import hello.core.order.service.impl.OrderSerivceImpl;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;


@Configuration
public class AppConfig {

    @Bean
    public MemberService memberService() {
        return new MemberServiceImpl(memberRepository());
    }

    @Bean
    public OrderService orderService() {
        return new OrderSerivceImpl(discountPolicy(), memberRepository());
    }

    @Bean
    public MemberReposotory memberRepository() {
        return new MemoryMemberRepository();
    }

    @Bean
    public DiscountPolicy discountPolicy() {
        return new RateDiscountPoilcy(); // 또는 RateDiscountPolicy()로 변경 가능
    }


}

이런식으로 @Configuration + @Bean으로 수동으로 등록하면

package hello.core.member.service.impl;

import hello.core.member.domain.Member;
import hello.core.member.repository.MemberReposotory;
import hello.core.member.repository.impl.MemoryMemberRepository;
import hello.core.member.service.MemberService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;


//@Component
public class MemberServiceImpl implements MemberService {

//    private final MemberReposotory memberReposotory = new MemoryMemberRepository();
    private final MemberReposotory memberReposotory;


    public MemberServiceImpl(MemberReposotory memberReposotory) {
        this.memberReposotory = memberReposotory;
    }

    @Override
    public void join(Member member) {
        memberReposotory.save(member);
    }

    @Override
    public Member findMemer(Long memerId) {
        return memberReposotory.findById(memerId);
    }

    public MemberReposotory getMemberReposotory() {
        return memberReposotory;
    }
}

MemberSeriveImpl클래스에는 @Component를 안붙여도되는거죠?

두번째 질문은 제가 알기론 컴포넌트스켄을 사용안하고 Component만 클래스위에붙여도 자동적으로 빈으로 등록되는걸로아는데 꼭 ComponentScan을 적용해야만 Component가붙은 클래스들이 자동적으로 빈으로 등록되나요?