It could be a bacterial leaf spot, as some infect Coneflower alongside several fungal leaf spots. Diagnosing the exact culprit can be challenging since symptoms often look very similar to each other. While broad-spectrum fungicides tend to be effective against a variety of common fungal pathogens, few fungicide sprays will be effective against bacterial pathogens. (The copper ingredient is a notable exception.) 

In either case, however, we do not recommend the use of a fungicide in this situation. Not only will it not cure existing disease or reverse its effects (if it works, it will only help to suppress infection on still-healthy new growth), but it risks harming pollinators or other organisms, especially given the appeal of Coneflower blooms to insects and, later, seed-eating birds. Fortunately, leaf spot diseases rarely cause serious damage to the plant they infect (eyesore aside), and usually do not require intervention. You can snip off any heavily-infected leaves if you prefer (none in the photos are what we'd consider to be heavily infected), but otherwise no action should be needed. If you water the plants during dry spells, try to avoid wetting the foliage (or at least avoid wetting the leaves close to evening), since prolonged leaf wetness can make foliage easier for spores to infect. If you can't avoid wetting leaves, like when using a sprinkler, try to water early enough in the day so that the foliage can dry by nightfall. Granted, you can't do anything about rain or dew, but that's one reason why plant infections can wax and wane from year to year -- because they can be highly weather-dependent.

Miri

Would putting down granular Infuse systemic fungicide in early spring help at all with the fungus issues that seem to inevitably pop up every year with my hydrangeas and coneflowers? 

No, a granular systemic fungicide will not be of any benefit in this case, as it won't be effective against this type of leaf spot disease. (That, and our plant pathologist says that they're not really as truly systemic as a comparable insecticide can be, moving up into the plant from root absorption.)

Hydrangea and Coneflower leaf spots are very common, though can be worse in years with wet weather (or with lots of irrigation that wets leaves often). Improving air circulation around the vulnerable plants can help suppress outbreaks because it keeps the leaf surfaces drier, but this is of course only of limited benefit since there is only so much thinning of dense branching or reductions in crowding that can be done.

These fungi spend the winter in infected plant debris lying on the soil surface, and while some spores resting on the soil surface directly are possible, generally they lay dormant in missed debris not cleaned-up after the fall killing frosts. Both can splash-up (or blow onto) new growth, generally in wet spring weather. While retaining leaf litter and dead plant stems as a mulch and refuge can be beneficial for overwintering pollinators and other organisms, this is one potential consequence of not removing it -- the harboring of pathogens along with any beneficials. Fortunately, the leaf spots are only cosmetic in their damage and don't cause the plants much (if any) long-term stress or weakening.

Miri

I removed two of the 4 hydrangeas on one side of my deck and now they have amazing air circulation! However, they are dense little bushes.  I will thin them next year, after they’ve had this year to recover from transplanting to their new spots.  They’re only 2.5 ft high at the moment, but full of blooms ☺️.  The copper soap treatment combined with scrupulous ground cleanup, new mulch + picking off all discolored/spotted leaves has obviously helped. 

Sounds like you've got a good approach! Good luck -

Miri