Free radicals and ions are quite different. Consider the .OH radical and -OH ion.
.OH radical - no charge, one unpaired electron
-OH ion - negative charge, no unpaired electron
Radicals have an unpaired electron, ions have a charge. They may or may not occur alongside one another. You can have ionized free radicals but it’s not always the case, as shown in the example above.
“Fortunately we have a product for people who aren't able to stay connected; it's called Xbox 360” - Don Mattrick, Microsoft's President of Interactive Entertainment Business
There’s no point as a swamp cooler does not have heat to reject. A heat pump in a traditional AC works by making one side hot (outside) and one side cool (inside). A swamp cooler decreases temps by evaporating water, which absorbs energy.
Also, swamp coolers are only effective in very dry environments. Unless you’re in the desert it’s going to make it feel warmer by raising humidity significantly. A large part of why AC makes it feel nicer is reducing humidity, which allows sweat to work better.
If it's lethal at high doses it’s not good for you, period.
The point I’m making is this statement you made applies to literally everything you can possibly consume. There’s nothing that’s not lethal or otherwise detrimental to life at a high enough dose.
You’re also using the appeal to nature fallacy when you say “if it’s not natural, it’s not good.” There are plenty of chemicals which are good, even lifesaving, that do not exist in nature.
“Drinking hot tea is safe so drinking boiling water, which is also hot, should also be safe”
The quantity of radioactive material and what form of radiation it emits is extremely relevant to this discussion.
We have seen nuclear batteries - it’s decades old technology at this point. They were used in pacemakers. They stopped in the 80s because it’s too expensive and dangerous. You have to track radiation sources like this.
In smoke detectors and tritium watches the quantity of radioactive material is minuscule compared to the beta emitter in the battery, as in multiple orders of magnitude less. None of the things you mentioned have radioactive material in any significant quantity. If you swallowed or inhaled this battery you’d be exposed to significant amounts of radiation.