Converting a race from handicap to SW&P is designed to retain its status by encouraging higher rated horses to enter, since they are better off at the weights. Can't remember the exact source for that, some article about the Telegraph a couple of years ago. While it can be seen as helping breeders, clubs and anyone else with an interest in races not being downgraded also benefit. Don't see any conspiracy.
The format is ok I dislike how it has changed the history of races though and left gaps in the calendar. How many handicaps are there left worth over $50k now up to a mile? Hardly any.