I only own one new model S&W revolver equipped with the ILS (lock). It's an early production M&P340, bought it in '05, before they offered a variation without the ILS.
I replaced the locking arm and torque lock spring after I came back from a factory revolver armorer class. Did it for the practice and because there was a revised spring listed. I've used that snub as a range beater, armorer "practice" gun (cut some new extractors) and a frequent off-duty & retirement weapon.
I eventually bought the new M&P340 variation without the ILS, so now I own a pair of M&P340's. They take turns being range beaters.
Oddly enough, I prefer to carry the older one, meaning the one
with the ILS, if they're both clean at the same time. The older one with the lock has acquired some scratches, dings, marks & rub marks ... but the dry & live-fire has given it a very nice trigger pull over the last 10 years. I also installed a set of Boot grips that add 1 ounce to the weight, making it tip the scales at 14.3oz (empty) instead of 13.3oz. It's simply a very nice handling and shooting snub.
In answer to the OP's question ...
While I originally tried the ILS to confirm normal functioning, including after replacement of the locking arm and spring, I don't use that feature, myself. I have a safe and a couple lock boxes that can be used to prevent any visiting grand kids from accessing guns.
I wouldn't mind seeing the company come up with a modified locking system that eliminated the somewhat obvious and glaring hole above the cylinder thumb latch, given my druthers.
FWIW, I've spoken with a few folks who said they used and liked the ILS feature, so I imagine it's appreciated by some owners (albeit probably not by many S&W revolver "traditionalists"

).