Is enduring the husband's injustice, miserliness, ill-treatment, and occasional beatings rewarded or sinful?

If the husband withholds his wife's rights, such as maintenance, and beats her and treats her badly, he is an abuser. The wife should endure his harm, and she will be rewarded for it. She should strive to reconcile between them, acting upon the words of Allah Almighty: "And if you fear dissension between the two, send an arbitrator from his people and an arbitrator from her people. If they both desire reconciliation, Allah will cause agreement between them. Indeed, Allah is ever Knowing, Acquainted [with all things]," and His words: "And if a woman fears from her husband nushuz [ill-treatment or desertion] or evasion, there is no sin upon them if they reconcile between themselves with a reconciliation - and reconciliation is best. And souls have been made to incline to [worldly] avarice. But if you do good and fear Allah, then indeed Allah is ever, with what you do, Acquainted."