Currently the tester allows you to use a comparison mode of Case Sensitive/Case Insensitive with greater than and less than operators. There may be good valid reasons why someone would want to consider 111 to be less than 20 whilst also considering 20 to be greater than 199 but I'd hazard a guess that these use cases would be far more rare than someone wanting to do a numerical comparison and having the incorrect comparison mode selected. Currently the In Range operator is only available when the comparison mode is set numeric or automatic, but greater than and less than are not restricted in the same way.
Additionally, it means that if you send string characters to a greater than/less than test that is set to automatic the test is attempted when it might be preferable to produce an error.