You ask why a person would want to? There are many reasons this person might want to do that. Maybe he/she is uninvolved, alone and find dating or searching for someone a real hassle and don't want to be bothered with the urges of sex when you can't find anyone. He/she may want to pursue spiritual matters. I really do believe this society should focus on ways to reduce the sex urge. We have all this talk about sex and v1agra and extenze and dating.com and findsex.com and all this stuff, but what about reducing the urge. Sex is important for procreation but it does have many many negatives. If the sex urge was reduced maybe sex crimes might be much lower. Maybe people can focus on more positive, creative things than looking for sex all the time.
I surely wish I could find something to almost eradicate my sex urge. I get so sick of people making a big deal about sex when there is so little real love in this world. I think sex can be a very selfish thing.