End of day your organic becomes magnesium and sulphur and npk .... soo its the same as synthetic you just have extra stuff from bacteria like some acids and who knows what.
True, once its ready to be taken by the plant its just bassically nitrogen, phosphorus and potassium. But there are major differences in synthetic compared to organic when it comes to whats inside the fertilizers besides the NPK. Here is a list of things you will most likely not find in synthetic nutrients that come inside organic and sometimes bio-mineral nutrients:
Vitamins: your plant produces them themselves but supplementing vitamins is always a good idea. In the wild, they have them, with synthetics they dont.
Humic and fulvic acids: improves root growth, good soil conditioners (improves the quality of the soil for the roots), improves nutrient uptake, reinforces plant inmune system, they act as ph buffers (they interact with acidic and alkaline compounds to regulate ph), and also work as nutrient buffers.
L-Aminoacids: synthetics use aminoacids made in a lab, theyre not L-aminoacids but rather D-aminoacids which the plants do not absorb as easily and they have less use for them too.
Natural plant hormones: they regulate plant metabolism and help speed things up, plants can also take more nutrients. You can use synthetic hormones but they will give you weird sponge like buds and theyre carcinogens.
Kelp is the superfood that brings most of them but theyre also present in many other organic ammendments, its just that kelp is the most complete one in terms of micronutrients and supplements. All organic lines that I know have kelp in either the base NPK or supplements, or even both.
I could keep going but I think you get the idea, if I make a complete list of things that you miss on using synthetics the post would be so very long.
I dont hate synthetics, sometimes less is better and for hydro theyre clutch but I dont smoke weed that is not organic anymore, I just like it better but thats a matter of personal preference too.