Let us say I've a DF created as follows

```
  val posts = spark.read
    .option("rowTag","row")
    .option("attributePrefix","")
    .schema(Schemas.postSchema)
    .xml("src/main/resources/Posts.xml")

```

What is the advantage of converting it to a Column using `posts.select("Id")` over `posts.select($"Id")`