Potions have some very fun, if not usefull abilities.
I use several for crafting. One of which will replenish my power bar in about 30 secounds.. Very nice as I can't cast breeze. However not very practical for adventuing as they dont stack so would take up a lot of inventory.
None of the other potions have been very usefull.. Poisons now thats another matter.
Note: Potions and Poisons have a Description, most are fairly usefull even if they dont give hard numbers.