The benefits associated with organic food are pretty well established and resulted in a sizable share of organic foods across all food categories. Now, how does that apply to organic spices and herbs? Generally speaking, probably even more than to regular food items.
That's because lots of spices are dual usage items, i.e., they have food seasoning and medicinal properties making it even more important to use high-quality spices that were not manipulated, contaminated, are pesticide free, etc.
Here is a list of general as well as specific health benefits of spices and herbs from an authoritative source (WebMD) - https://www.webmd.com/healthy-aging/over-50-nutrition-17/spices-and-herbs-health-benefits
and another link that focuses more on organic food facts - https://www.organicfacts.net/health-benefits/herbs-and-spices/spices.html
Of course, there are plenty of opinions available online that urge you to move quickly toward organic spices - https://foodbabe.com/are-there-harmful-ingredients-lurking-in-your-spice-cabinet/
And lastly, it is always important to understand why we eat what we eat, here is a brief blog post that also highlights the history of spices - http://www.streetdirectory.com/food_editorials/cooking/herbs_and_spices/the_benefits_of_using_organic_spices.html