用rds不需要理由吗？给我一个用rds的理由先

我的网站放了一份数据在本地mysql，又放了一份在rds上的mysql。ab测试首页，发现rds比本地的要慢

ab -n 100 -c 4 http：//xx.xx.xx.xx/
==========这是本地的分割线===========================
Total transferred:      807900 bytes
HTML transferred:       760800 bytes
Requests per second:    81.95 [#/sec] (mean)
Time per request:       48.808 [ms] (mean)
Time per request:       12.202 [ms] (mean, across all concurrent requests)
Transfer rate:          646.59 [Kbytes/sec] received
==========这是rds的分割线===========================
Total transferred:      807900 bytes
HTML transferred:       760800 bytes
Requests per second:    59.27 [#/sec] (mean)
Time per request:       67.488 [ms] (mean)
Time per request:       16.872 [ms] (mean, across all concurrent requests)
Transfer rate:          467.62 [Kbytes/sec] received

我想rds应该是有其自身优势的，那么rds的优势主要体现在哪里呢？