Driving difference between the duo:
Appreciate vs Encourage
Appreciation is more about estimating a person's past activities.
This act puts the person into a trap of what he/she did.
But not motivates to proceed further.
Encouragement is an act of motivating the person to do more.
This act refers to the present and the future of a person.
Concluding that, encouragement is good that motivates a person to achieve more. Whereas, appreciation lets the person feel he/she achieved the peak and attained saturation. This puts the growth of the person to an end.
Think before you act!