why we need @Param on spring boot code example

Example 1: spring url parameter

@RequestMapping("/{someID}")
public @ResponseBody int getAttr(@PathVariable(value="someID") String id, 
                                 @RequestParam String someAttr) {
}

Example 2: spring boot param object

@RequestMapping("/{someID}")
public @ResponseBody int getAttr(@PathVariable(value="someID") String id, 
                                 @RequestParam String someAttr) {
}