The resistance is on the lower end of acceptable, but that may be because spark plug resistance tends to drift upward over time.
From what I can gather, the ignition coils are sensing ionization current and feeding that information back to the ECU. Depending on how advanced Mazda's implementation is, the ECU can determine if the combustion event occurs "as planned" vs. a misfire or a preignition/detonation based on the current flow across the plug gap and how it varies over time. This info can then be used to adjust timing on a per cylinder basis rather than on all cylinders in bulk.
Other OEMs have been using this technique since the 1980's, with varying levels of capability. If you want to experiment, be on the lookout for misfire check engine lights and a code reader might be a good idea to check for misfire counts (record this before and after swapping plugs).
I'd probably just stick with OEM spec plugs.