You're not limited to calculating a formula based on a role, each individual row can have its own formula (say each employee can negotiate their own salary/comp

You're not limited to calculating a formula based on a role, each individual row can have its own formula (say each employee can negotiate their own salary/compensation package). You would need a union of an infinite number views to equal the number of formulae possible with an expression column type. So it's definitely more expressive and powerful.