Restraining the nafs from evil and transgression is an act of high piety and great merit. By means of constant and perpetual restraining of the nafs from evil a man gains close proximity to Allah Ta'ala even if he perhaps have few acts of ibaadat to his name. Abstention from sin and transgression is of greater importance and has greater merit than Nafl acts of ibaadat.
Restraining the nafs from evil is an Amal Baatin (a spiritual act) which is not generally considered to be an act of ibaadat by those who lack understanding. Considerable barkat and piety are achieved as a result of always restraining the nafs from sin and transgression.