-1 Anything the notes will do you can do yourself. The point of skyblock is to be a challenge.
Fly note? Just build a pillar and mine back down or use water.
Feed note? Eat some food.
Fill note? Use your cobble and buy lava or water.
Heal note? Just wait and regenerate the health.
There is no point in adding it into skyblock as it will become a convenience. And to it becoming a reward to high challenges or sold in shops, I don't believe it will be worthwhile in the long run as people will either abuse it to derail the economy of lava buckets/water buckets or more trouble than it is worth.