For some statistical tests it is possible to check if the comparing data-set is bigger or smaller or not equal. Testing if the data-set is bigger or smaller gives a 2 times more significant result because this is a one sided test. In some statistical environments it is not allowed to use one-sided tests. The safest test is not equal and is used as the default setting.
In Develve the p value when using bigger/smaller is always halve of the value when calculated in not equal mode. You self have to look if it is bigger or smaller than the comparing value. This increases the overview of the results.