It will reduce complaints because your recipients will be able to easily and reliably unsubscribe if they want to. Frustrated users are likely to hit the "Report Spam" button or complain in some other way about the email that they requested, hurting your sender reputation.

Install with Composer as you go

Go to Magento2 root folder
Enter following commands to install module:
```
composer require faonni/module-newsletter
```
Wait while dependencies are updated.

Enter following commands to enable module:

php bin/magento setup:upgrade
php bin/magento setup:di:compile
php bin/magento setup:static-content:deploy  (optional)