It seems that those add on's are just gadgets but they really do work WELL for the PRS/NRL type games. The extra weight of the chassis system and being able to quickly position the bipod on the ARCA rail can make a BIG difference when balancing the gun off of obstacles.
I have a 22rf that is lower weight and back in the day I would win NRL22 matches often with it but some friends built Vudoo bolt actions with heavy barrels off of heavy chassis systems and all of a sudden I wasn't able to compete at their level. Their guns just sit there very stable when balanced off of barricades and other obstacles, whereas mine wobbles around a lot in comparison. It's basically the difference between winning the match or finishing 3/4 the way up the roster nowadays!!!! That's one reason I quit going to NRL22 matches because I'd have to invest $3000 more to get a new gun to compete with, eh I'm getting old is another good other reason.