[Dúvida] Exercício grid

Fiz o exercício, mas usei as propriedades justify-content e align-item, o instrutor não usa essas propriedades para resolver, gostaria de saber o porquê disso.

meu código:

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

.corpo {
    background-color: #444444;
    padding: 8px;
    width: 100vw;
    height: 100vh;
    display: grid;
    justify-content: space-between;
    grid-template-columns: 1fr 1fr 1fr 1fr;
    grid-template-rows: 1fr 1fr 1fr 1fr;
}

.cabecalho {
    background-color: #cc2a2a;
    border-radius: 10px;
    min-width: 50px;
    min-height: 50px;
    margin: 8px;
    grid-column: span 4;
    grid-row: span 1;
}

.lateral {
    background-color: #45cc2a;
    border-radius: 10px;
    min-width: 50px;
    min-height: 50px;
    margin: 8px;
    justify-content: flex-start;
    grid-column: span 1;
    grid-row: span 3;
}

.meio {
    background-color: #2aa6cc;
    border-radius: 10px;
    min-width: 50px;
    min-height: 50px;
    margin: 8px;
    grid-column: span 2;
    grid-row: span 3;
}

.direita-cima {
    background-color: #352acc;
    border-radius: 10px;
    min-width: 50px;
    min-height: 50px;
    margin: 8px;
    justify-content: flex-end;
    grid-column: span 1;
    grid-row: span 1;
}

.direita-baixo {
    background-color: #cc2a96;
    border-radius: 10px;
    min-width: 50px;
    min-height: 50px;
    margin: 8px;
    grid-column: span 1;
    grid-row: span 2;
    justify-content: flex-end;
    align-items: flex-end;
}

![Resultado exercício grid](https://cdn1.gnarususercontent.com.br/1/1337003/b3501170-f614-4b9d-be92-0c56426ef0a0.png)