When signing an expression, it might be invalid - which will result in the blindsigning flow being triggered.
Since expressions are much less critical than operations (e.g. being used for sign-in flows), it's not as bad to blind sign them, if they are formatted incorrectly.
Therefore, it could be reasonable to enable blindsigning for expressions, while wishing blindsigning to be disabled for operations still.
When signing an expression, it might be invalid - which will result in the blindsigning flow being triggered.
Since expressions are much less critical than operations (e.g. being used for sign-in flows), it's not as bad to blind sign them, if they are formatted incorrectly.
Therefore, it could be reasonable to enable blindsigning for expressions, while wishing blindsigning to be disabled for operations still.