For me, it comes down to getting the chlorinating liquid vs. making it at home. I don't want to carry liquid chlorine or drive to get it.
To be fair, even with an SWC, you'll buy a few jugs each year for top-ups, unexpected large bather load, contamination events and for chlorinating when the water is cold. I used 20 gals that way last year including one SLAM.
SWC users tend to consume more liquid acid than people without an SWC, and have to replenish salt. The amount of liquid acid will be much less than the chlorinating liquid would be, but enough that it's worth mentioning. I used 5 gallons of acid last year and three 55 lb bags of salt, while my SWC made the equivalent of 60 gallons of 12.5% chlorinating liquid.
Both systems require testing and adjustment to maintain the desired chlorine level. Chlorine depletion varies from day to day and week to week depending on weather and bather load, so that comparison is pretty much even. With SWC, you adjust a dial or push buttons. With a liquid dosing pump, you can change the setting to provide more or less chlorine for an upcoming period.
A salt water pool with a SWC is better for me, and I wouldn't own a pool without one. If SWCs weren't available, I'd have a Stenner pump for dosing liquid.