We tend to get these questions even though we are in the business from few years. One tends to feel that, a great strategy that has been abused by many to bits.
Yes, for trade anything that brings in audiences to the theaters or even increase buzz of the film is a great strategy. As part of promotional campaign, many are including success meets as a part.
As the actors have to be informed early enough about every press tour and take dates for every single meeting that producer wants to conduct, post release press meets and success meets are planned well in advance.
These used to be a great strategical meets as people used to feel that the mouth talk they heard from their friends group could be false and someone somewhere is watching the film.
Today, they have become an extension of promotions and off no meaning. ANR and NTR used to visit theatres only when their films crossed 100 or 150 days of exhibition that too at special requests.
During Krishna and Chiranjeevi time, success tours of landmark hits used to be very common. They went a step ahead in late 80's and conducted public success events on large scale until there used to be closed door parties and rare visits to special theatres.
During 90's every producer started organising success tours after 3rd or 4th week, when collections used to take a dip for a film that managed to become a hit. In 2000's again this became rare as stars did not want to be so visible and easily accessible.
But in 2010's, the post release success meets have become a big deal. They have become a compulsion to such an extent that until hero or producer cancels the event, press is invited to them and there will be tours to theaters, no matter however the movie is performing.
It genuinely started as a "Thank You" to audiences and fans of the films and now they have become "Compulsion" meets. You see all of the young actors ready to take off clothes on stage if it helps to promote their film and post release success meets and tours for even small films seem just an abuse of strategy than showing the worth of the film.