“Synthetic” vs. “natural” is in most cases a relatively meaningless distinction, used as a marketing gimmick because we have positive connotations with the word “natural” and negative connotations with words like “synthetic” and “chemical”. If a synthetic version of a vitamin is literally the same vitamin as something harvested from natural sources, it will be identical and have identical effects. Sometimes, there isn’t a commercially viable process to synthesize a vitamin in the form that is found in nature, and then you can have differences in bioavailability and toxicity. Vitamin K3 was one such compound, and it has been banned in supplements.
It really varies from compound to compound. Sometimes the “natural” form of certain things is actually worse because of what they have to do to harvest it. In particular, a lot of food products like to advertize “naturally flavored”, but artificial flavoring is generally purer and more free of contamination and is made up of compounds that are known to be safe.
The article you linked to doesn’t provide any sources. A lot of what gets said by the supplementation industry is a lot of pseudoscience. I’m not saying that there may be differences between natural and synthetic ingredients, but what I am saying is that people who have the heuristic reflex to say that they only eat foods that are “all-natural” as though that really means something are probably getting sold a bill of goods. An ion is an ion is an ion, and if it’s laboratory grade it doesn’t matter how they got it.