Potions are infinitely more useful than an upgrade of armor or a slightly better weapon.
The perks are great too. 
Double effectiveness, longer duration, wont be forsaken over a different piece of shiny metal.
Everyone is gonna flood the market with weapons and armor to a point when sales are driven by who has the rarest one. Everything else will be "top tier or not at all"
Whereas a potion of attack speed will always sell in large quantities. 
Repair powder will be another fun alchemy perk. I bet there would also be various fluxes and flasks blacksmiths would need mix with a recipe to get higher stats of a certain kind. 
We also make great use of poison! Which I doubt SAO ever mentioned but can't not be in the game. This is still an MMO.
Enjoy your durability while you can.