I was going through an online video and the author had the below code:

  public async Task CreateBookAsync(BookDto newBook)
  {
    var book = new Book(newBook.Id, newBook.Title, newBook.Author, newBook.Price);

    await _bookRepository.AddAsync(book);
    await _bookRepository.SaveChangesAsync();
  }

BookRepository:

  public Task AddAsync(Book book)
  {
    _dbContext.Add(book);
    return Task.CompletedTask;
  }

  public async Task SaveChangesAsync()
  {
    await _dbContext.SaveChangesAsync();
  }

I was not sure why AddAsync returns a Task and not just void, why have return Task.CompletedTask. Is it because the CreateBookAsync is using async Task, its beneficial to keep all methods within using Task? Would it make a difference if it just returned void?