It doesn't matter how the ionization occurs. At the end of the day, you end up with metal ions in the water, most notably silver and copper with the former a little better at killing bacteria and the latter better at killing algae. However, both kill fairly slowly taking hours for significant reductions and they don't do much with viruses. With chlorine, even with CYA in the water, the time to kill 99% of most bacteria is around 1 minute. So using metal ions or metal storage containers for standing water is one thing (i.e. the NASA reference), but that's not the same as a pool where new bacteria, viruses, cysts, etc. are potentially getting introduced into the pool water via fecal matter, among other things.
The reason for chlorine, or other EPA-approved sanitizers (bromine, PHMB/Baqua/biguanide) is that they kill pathogens VERY quickly in the bulk pool water thereby helping to prevent person-to-person transmission. This is why ionization systems, by themselves, are not used in commercial/public pools. Certainly the risk is lower in a residential pool environment, but you are much safer using an EPA-approved sanitizer than only a metal ion system alone.
Richard