PHP - Logic handling

I like to know what the advantages to putting the logic in separate classes rather than putting all the logic in the RuleManager class.

For example

Separate the classes for each responsibility

class RuleManager {

    public function create(string $name)
    {
        return (new CreateRuleCommand($name));
    }


    public function list()
    {
        return new ListRulesCommand();
    }

}

vs:

class RuleManager {

    public function create(string $name)
    {
        // Do all the create logic Here

        return $something
    }


    public function list()
    {
        // Add all the listing Logic Here

        return $something
    }

}