Its more than "mildy" effective. It was used to treat serious life threatening illness. Granted, that was before we had better antibiotics like penicillin, but this wasnt just for cuts and bruises or the sniffles or a sore throat. This was the go-to drug when your life was in danger from a bacterial infection. It worked pretty well.
Its true that some other forms of silver are more potent, but they are also a lot more toxic for internal use. I am not a doctor (I have pre-med education and a degree in nutrition/dietietics, some knowledge of basic chemistry, ect), but for internal use I would consume colloidal silver before drinking silver nitrate or eating silver paste used for burns.
Colloidal silver is NOT necessarily better than other prescription antibiotics. The main advantage is that its easy to make on your own (but not cheaper if made large scale in a lab compared to penicillin), fairly safe, and very effective against serious life threatening illness in the right dosage. Perhaps not as effective as penicillin, which is cheaper to mass produce, but effective enough for something you can make in your kitchen.
If you are using the little electrodes you can buy on ebay, that is not true "colloidal silver". Its actually ionic silver. Ionic silver also shows promise for fighting infections, but I dont think there is much serious research on its use in medicine. We have drugs that are cheaper to mass produce that are more effective.
Colloidal silver can kill some nasty infections. It can totally eliminate an infection, even a serious one. People have survived because of colloidal silver where they might have died.....they used really potent silver though at doses with put mild strain on the kidneys, but your skin is likely to turn blue before other more serious side effects manifest. Its a good warning sign. If it wasnt permanent I would say that its an awesome warning signal.
But no, its not just "mildly effective" if you are talking about the original strength used in western allopathic medicine. Other forms might be stronger (silver nitrate), but they are more toxic, and the trade off is not worth it....at least for internal use. Maybe not for external use.
Colloidal silver would be a great thing to know how to make in a disaster zone when you dont have access to conventional antibiotics. It can be used to purify water to make it drinkable (though it wont filter toxins).
I think that being able to make an effective antibiotic in your basement is empowering. Its not better or even safer than conventional antibiotics, but its a level of technology that anyone can have access to in a disaster zone....you never know if you might end up in a hurricane katrina type situation where you need to make sure you dont get disease from the water, assuming there isnt a way to boil it or you dont want to waste what you have in evaporation, or to treat the sick with nothing but a piece of silver and some electrodes. I think its pretty cool.
FYI, the stuff you are making is possible 0.03% of the potency of the stuff they used in emergency medicine. It might take a lot to kill a serious infection.....you might want to see if you can find some research, even small scale anecdotal research, to get some idea of how potent your stuff is and what dosage is effective at that potency.