Asceticism is self-denial in unnecessary things. Asceticism is self-restraint and thrift. You save energy on the harmful and useless in order to spend it for good.
The goals are austerity and self-restraint. To achieve your goals, you need to cut off excess and avoid the temptation to deviate from the path of truth.
The essence of austerity is the preservation of love and joy. Exhaustion and overabundance kill happiness, love, joy, and all the other pleasures of life.