DBA told me to do this but did not say why or its advantages? Can someone help

This is my present table:
CREATE TABLE IF NOT EXISTS `geocode_us` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`loc_b` varchar(32) DEFAULT NULL,
`loc_a` varchar(32) DEFAULT NULL,
`lat` varchar(16) DEFAULT NULL,
`lng` varchar(16) DEFAULT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `idx_name` (`loc_a`,`loc_b`,`lat`,`lng`),
UNIQUE KEY `idx_name2` (`loc_a`,`loc_b`),
UNIQUE KEY `idx_name3` (`lat`,`lng`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=81814 ;
He says to do…
DBA told me to do this but did not say why or its advantages? Can someone help

See original post by Brad77