Allah looks for any excuse to show His mercy did you know that? Allah tells us when we seek forgiveness, He will forgive us.
If we didn’t seek forgiveness for minor sins, but we are doing good deeds consistently, these good deeds will wipe out the minor sins.
What about the major sins? We can’t just seek normal forgiveness, we have some steps to follow for a specific repentance for a major sin. Once we have fulfilled those conditions of the repentance for the major sin, then we are forgiven.
Allah tells us to seek repentance constantly. This is not because we doubt the mercy of Allah but it is because seeking forgiveness constantly brings us closer to Allah.