The dot operator works only when the thing on the right is a bean property or map key for the thing on the left. That’s it. But the [ ] operator is a lot more powerful and flexible...

This:

${person["name"]}

Is the same as this:

${person.name}

The simple dot operator version works because person is a bean, and name is a property of person.

But what if person is an array?

Or what if person is a List?

Or what if name is something that can’t be expressed with the normal Java naming rules?