Essentially, yes.
The salt in the pool is never really used up - the Chlorine is broken out of the salt (sodium chloride) and then eventually recombines in the pool returning back to salt.
I'm not a chemist, its a bit magic really, but that's basically the way it works
The Salt Cell of the SWG has some fancy materials that allow for that Chlorine to be broken out of the salty water by the electricity.
Over time, those fancy materials erode/corrode/wear out, and the cell loses effectiveness.
The cells are rated in # hours @ 100% power - so you could think of it as basically a big jug of chlorine...it's just the chlorine is really stored in the pool in the form of salt, and you 'activate' it by electricity.
You may need to top up the salt occasionally (like maybe a bag or two once a year to account for rain dilution etc) - but salt is about $6 for a 40lb bag.
If you are spending $500 a year in LC, an SWG
WILL be cheaper just about any way you slice it.
Here's a quick post-it-note calculation assuming you use $500 of LC a year.
I'm going to figure 100 gallons of 12.5% - that's about 833ppm over the year, or 2.5ppm/day
Assuming you went with the Circupool RJ-45+
$1200 initial outlay
15000 hour life @ roughly 4hours /day required to produce 2.5ppm = 3750 days, or 10 year life
Replacement Cell is $694 - so cost per PPM of Chlorine is essentially $0.07 - versus 12.5% at $5/gallon = $0.60

(I'm sure
@Newdude will check my numbers!!)
So your initial investment would be paid off in basically 2.5 seasons - your cost would then essentially drop to about $70/year (not counting electricity which is fairly minimal)
And, you've just future-proofed your chlorine cost - if chlorine goes to $10/gallon...who cares?