I experienced very slow chunk generation when using an elytra and it annoys me to constantly die is survival mode because of this. I also unlocked an adventure map called Terra Swoop Force and there the slow chunk generation is creating big issues. No matter what i do i always end up suffocating (in my default worlds) or exploding (in that adventure map).
The world chunks generate right then when i am technically inside a block (spot generation).
I have a low end device (2 to 3 years old) but it still works perfectly.