Is Impurity The Only Reason Related To Menses?
The situation is unique to women because their biological construct is different to men and Sharia gave due regard to this reality. Had Shariat not given any directive in this regard, scholars would have done ijtihad in this regard as well, the way they do for a sick person having incontinence problem, for example. But since women make up more or less half of the population and they have to experience this situation once every month unlike comparatively few medical cases of permanent bladder problem, therefore, this matter was taken up by sharia and explicit ruling was given. And when we try to understand this directive in relationship with spirit of the religion, the buck stops at Taharat ( Tazkiya ). No it is not a form of worship and yes, this underscores the importance of Taharat in addition to it being an actual criteria for success in the eyes of God.