Since .sif files are just XML files under the hood I guess it would be possibile to make a synfig animation library for use in games frameworks like raylib or a flash-like viewer in HTML5. Just a hypothetical though 
While it’s not impossible, it would require a lot of resources and not reliable on every machine.
Lottie is more adapted for such purpose.
Just think about how much it sometimes lags already with C++ and like seen in the recent topic about preview glitches on a “weak” computer
When/If we have ported all layers to Synfig Cobra renderer, it would be easier and safer to use openGL, and then maybe - who knows - perhaps - we wish - we - someone - could do it 
I guess a good compromise is to export to lottie format and find a library that adds lottie support for the game framework i want to use
Do you want it as a cut-scene or something like that?
That and as a sprite.
For sprite, you can export using “spritesheet” as “target” on render dialog.