With a less than operator and the ability to encrypt chosen plaintext values, you can decrypt arbitrary messages in a linear (in message size) number of steps.
Arithmetic operations can often be used to build gadgets that bootstrap comparison operations. For instance, with addition and equality you can implement a comparison operation for low-medium cardinality fields.
The field is littered with negative results that are being sold as secure, practical systems. Be careful when using them on important data.