What are ChuChu Jelly utilities?

ChuChu Jelly (the blue kind) can be 'empowered' into the various colors of elemental ChuChu jelly by exposing it to that element. (I.e. For red jelly, put it in a fire, for white jelly, put it down in a cold snowy area, etc.)

Elemental ChuChu jelly, like the ChuChu's themselves, explodes when impacted in an elemental burst. Icy jelly will freeze enemy, red jelly will start fires and detonate explosives, etc. you can abuse this by, for example, placing a jelly on the ground and firing an arrow at it to detonate it.

In addition, the elemental ChuChu Jellies are more valuable. Potions made with them rather than regular jelly will be more valuable. The easiest way to use it is to drop a large amount of regular jelly on or near a fire, then make potions using several of the Red ChuChu jelly.

Adding to @LessPop_MoreFizz's answer, the jellies are also fairly valuable to be sold. The unempowered blue ones aren't worth much, but the empowered ones are fairly valuable, especially once you consider how common they are. Easiest way to convert the blue ones into fire ones is to travel to the hot areas of Death Mountain, and drop them on the ground and wait a couple seconds. It accomplishes the same thing as dropping them in a fire, but you don't have to aim. You can do the same traveling to the snowy areas north of the Rito Village and drop them in the icy water to turn them into cold empowered.

Also, if you meet Kilton (start that by going to the skull shaped lake North East of Death Mountain, you can sell monster parts for a unique currency called Mon. The jellies are fairly valuable as rupees, but arguably more valuable in Mon, as there are a lot of unique items you can only get from him, like a Dark Link clothing set that lets you run faster at night. Also a monster themed saddle and bridle for your horses, and more. Exchanging my elemental jellies for Mon is how I bought most of his inventory.