Abstaining from all sexual contact is a useful solution for some people some of the time – say when people are too immature or financially unstable to handle a relationship or a child. It can be empowering to say no to sex. Especially when one is being pressured to have sex – pressured by a boyfriend or girlfriend, by friends, by yourself. Saying no then can give a person the valuable experience of feeling one has taken control of one's life. Choosing abstinence – if one means by it no sexual contact with others – does not necessarily preclude all sex.
We live in a sex-drenched culture. It is estimated that three of four USA high school students said they had had sex by the time of graduation. People are not automatically emotionally, intellectually and financially ready for coupling when they are physically ready. Sexual abstinence is a guarantee against contracting sexually transmitted disease and unwanted pregnancy.
Sublimating sexual energy can be very useful for getting necessary things done in one's life.
Masturbation is a useful way to channel one's tensions when wishing to abstain yet is feeling the urge.
Sexual abstinence is not really an absolute concept. Depending on how one defines it, abstaining may mean doing everything else conceivable up to intercourse. Or oral sex. Or petting. Or kissing. Or flirting.
On the other hand, too much channeling of sexual energy into counter-productive activities is worse than if you had just gotten off and gotten over it.