These O2 sensors have been in industry for a lot of years, no different than galvanic cells, diving is not a priority for this market.
So, they can survive a bath in caustic with no issues? Galvanic cells can usually handle that and continue to be used (on future dives). You're saying these SS sensors are no different, so they can also handle a caustic bath and generally be expected to continue to work after cleaning up post-dive?
As far as safety improvements, it is about failure modes. Failure on a galvanic cell usually results in inaccurate readings which have lead to fatalities and near-misses because people think they are breathing one gas and not what is actually in the loop. Solid state cells when implemented in a full digital system have signal validation and are either "working" or "dead", no risk of misinformation from the cells is a huge safety improvement. I'd much rather a cell be dead than have it give me bad information
And so we have 3, 4, or 5 cells. How many CCR divers have been injured or died in the last, I don't know, 5 years, who followed their training (including maintenance), because of misinformation from their O2 sensors?
Even anecdotally. How many have you heard of?