One of the many reasons are people are free to enhance their intellectual growth through pursuing education, something the WTS demeaned for very much of its existence. Education is a good thing for humanity for knowledge can and does help resolving some of the problems mankind has to endure. ... ie. new discoveries in health and medicine.
Once free from the oppressive resistants of the WTS and its leaders one can pursue a vocation in politics or let their children join the Boy Scouts or Girl Guides and yes organized politics can help humanity if its done right with empathic good will intent for the people, some of those established ideas that many of us now usefully enjoy and appreciate.
Another is the non restraint on who you can or should associate with on a social level.
As JWS you are always controlled onto who should be your closest friends and that is enforceably
influenced to be other JWS only.
The problem with high controlling cults like the JWS is that they take away ones own individual freedom to choose their own direction, instigating elements of fear and provocation for people to remain within the organization and strategically support it fully without questioning scrutiny.
Many people have lost their families due to simply pointing out the false information and doctrines that WTS. created to allure people to the organization in the first place.
Not to mention the thousands of people who faithfully obeyed the leaders of the organization concerning serious health issues and died as a result for not taking a blood transfusion, vaccination or organ transplant.
So what are some other things one can benefit from leaving or being Dfed from this encouragingly backward cult of inherent deception and corruption ???