Yes, they seem insignificant but I think they are one of the best prizes you should have in your arsenal, especially if they are legendary potions. Every time you open a chest with cards, one of these potions is used automatically, increasing your chance of getting a legendary one.
I think that one of the best long-term strategies in splinterlands is to accumulate as many of these potions as possible, especially if they are legendary. The worst that can happen to you is that you run out of potions.