When making animations and/or sprite sheets for a game engine, you have to figure out what file type is compatible with the game engine you wanna use, save each of them as individual files, and then move those files onto the game engine to use them. That takes a lot of time, as well as some research, to figure out how to do all that.

I would love to see Aseprite have a future ability to import the animations you make directly into the game engine you wanna use. You basically go to Import in the File tab, and then click Game Engine. It then brings up a window that lists the game engines currently installed into your computer, and users can choose which game engine you'd want to import it into. This'll shorten the time usually used by importing them directly into the game engines's project as a compatible file, as well as generate any other files needed for it to be used.