Resellers need a way to keep track of your offerings, quantity and available upgrade/addons.
It is extremely time consuming trying to get the information from the page and then have to go through each ones available upgrades.
It would also be a bit of a headache if a client orders a server only to find out no more available or it is outdated.
Maybe a downloadable CSV file although that would be a pain dealing with upgrades.
The best would be for those using WHMCS an import module of all available offerings with self population.
I use one right now to connect to my domain registrar, I just tick what I want and set a price and it imports everything for me.