Copper not only kills bacteria more slowly than chlorine, but at the levels allowed in pools copper ions do not kill nor inhibit fecal bacteria AT ALL. This is because the level of copper ions in your gut where such bacteria live (in controlled numbers by other more beneficial bacteria and immune system components that keep them in check) has around the same level of copper ions as in a pool (if not higher). So these bacteria evolved mechanisms to handle low levels of copper ions. Technical details and kill times for chlorine, copper and silver are found in this post. If one is going to use a metal ion system, and I'm not recommending that, it should be a copper/silver combination system so that at least one gets some control of fecal bacteria. However, staining is an issue unless one carefully controls the metal ion levels and keeps pH low.

By the way, if one wants to have a lower chlorine level (FC/CYA ratio) and therefore lower chlorine usage from its breakdown from sunlight, then one can use an algaecide such as PolyQuat 60 added weekly and not get the risk of metal staining of pool surfaces nor of blonds getting green hair. Another alternative is to use 50 ppm Borates in the pool, though that's a milder algae inhibitor than copper ions or PolyQuat, but doesn't have staining side effects and doesn't need to be added weekly. For some pools, it's enough to keep algae from turning into a bloom for at least a week or so (based on both waterbear's and my own experience).