The new Slime Armor is being regarded by many as one of the coolest armor sets Minecraft has ever seen.
The boots can make you bouncy and negates all fall damage, which can be great for speedruns.
The helmet allows you to hang from blocks, which allows you to hang from ceilings like Spiderman.
If you wear the full armor set, you get a permanent jump boost.
If you go to the Nether and craft the Magma Slime Armor instead, you get the Fire Aura ability that will deal damage to all nearby enemies just by being near them.
You should set up a slime farm to get the new armor set as soon as possible to try out all of the fun stuff the Slime Armor and Magma Slime Armor enable in Minecraft.