Is there anything in the world which is not a double-edged sword, something completely devoid of downsides? AFAIK only certain transcendent entities are declared to have this property.
Do you mean personal downside or societal downside? It could be argued that a well developed persona covering up innate sociopathy would be highly beneficial to a person and have no personal downsides, as long they as truly didn't care about others.
Just because anything has drawbacks if you look hard enough doesn't mean that it's impossible to differentiate innovations on that criterion. Surely you can see how aspirin is not as concerning as leaded gasoline.
Each and every parameter (even "population size") has an interval of 'adequate' values. Too few of anything, or too much of it, leads to major downsides.