The main benefit of loop and reduce is files are split into multiple qvw files based on the reduce field selection while reload. So for each individual file will provide the access role based on the requirement. So if user does not have the rights to see then that file is not available to that user. This Performance is more better, bcoz file is already reduce into multiple files.
While in the Section access application contain all the data initially in a single file only, so based on user access role it will reduce the data when user is checking on access point. This approach is taking more time due to reduce the data based on the credential provided.
If you use Loop and reduce there are multiple qlikview files generated based on the reduce field selection while reloading. For each and every document you have provide access in Server this is bit difficult, if you are not using server then you have distribute this files via email or any other method. This method has better performance because data is less, but difficult to maintain.
If you use Section Access there is only single file which handles the authorization, based on the user the data is shown in the dashboard. By using this method it is easier to maintain the files, also it has more security.
