Actually i didnt understood this section clearly.
" We encourage everyone to use Moddio as it has built-in token integration, but it is not required. "

If i use different engine, dont need token integration or is it not required Moddio?

You may use any game engine. You do not need a token to be integrated upon submission, but you should have some in-game currency so we can understand how the token will be integrated in the future.