My understanding of Aetheryte travel is that literally anybody can do it to any distance and location, as everyone has some sort of store or reserve of Aether in their being. That energy is consumed and used to resonate with the crystal and transport you on the Aetheric stream. However, the amount of aether reserve you have available determines how far and how and often that you can use this method of traveling before it starts to become detrimental to your person. However, since the Aetherytes that we have access to are all in Eorzea, we can freely use them to transit about without concern of any single given transit immediately effecting us negatively. That said, the City-States discourage over-use of this convenience since you really have no way to gauge how many is too many, and so people still tend to use conventional means of travel as a regular day to day.
Basically, everyone should have little to no problem with using Aetheryte to make expeditious trips without concern or cause of worry. People who are strong at using or manipulating Aether can use it even more so, with those who are not familiar with it probably only using it excessively at their own risk (or their lack of care or understanding) with there probably being a good probability of repercussion. People use other methods of travel simply because it's safer or because it's the only way; there's no demonstrated use of Aetherytes for transit of goods, so merchants and their sellsword guards would certainly have to hoof it on foot. People who are just overly cautious or suspicious of such magic would probably never use it, either. There's probably a handful of people who are just Aether inept who this kind of travel is probably ill advised to, as well.
Basically, everyone should have little to no problem with using Aetheryte to make expeditious trips without concern or cause of worry. People who are strong at using or manipulating Aether can use it even more so, with those who are not familiar with it probably only using it excessively at their own risk (or their lack of care or understanding) with there probably being a good probability of repercussion. People use other methods of travel simply because it's safer or because it's the only way; there's no demonstrated use of Aetherytes for transit of goods, so merchants and their sellsword guards would certainly have to hoof it on foot. People who are just overly cautious or suspicious of such magic would probably never use it, either. There's probably a handful of people who are just Aether inept who this kind of travel is probably ill advised to, as well.