When you:
/effect <YourUsername> minecraft:levitation 60 254

you fall very slowly. So how do you die/take damage when you land slower than a chicken? Also when you hit the ground and it's not enough to kill you for some reason it launches you back in the air?

This is very confusing and doesn't make much sense... hopefully the taking damage is a bug and not the falling slowly (If you set the level of effect to 255 you hover which is cool too)