The article is not accurate in some places. E.g., some coin cells are rechargeable such as the LIR2032.
Fortunately the actual page on li-ion gives 3.6V
Personally I think the safety risks of using li-ion cells like 18650s are a bit overexaggerated -- the torch/"vape" community has been using them in large quantities (in China they are becoming nearly as common as AAs), and there have only been a few notable cases of significant damage. Yes they are not as safe as something like an alkaline but even lead-acid and NiMH/NiCd can source significant amounts of current too.
The benefit is that they do not explode and proven to be safe choice when you need high drain batteries. Granted, you need a good charger for them, to make sure you're not overcharging them, but this should be on your safety list anyway.