[syntheweave]

Originally the style in gaming came about through two related influences:

1. Flash and its status in the 2000's as the tool every animator cut their teeth on. Flash makes it easy to paperdoll things with scenegraph relationships, though it has no skeleton system per se; if you animated the doll by hand and set up your assets proportionately you were good to go on making games with character creation, visible equipment etc.

2. Texture memory limitations imposing limits on keyframe animation in mobile games. This led the larger mobile companies circa 2010 to build out proprietary systems that would get the most out of relatively small textures and make them modular assets for everything - UI, animations, backgrounds, collision bounds, FX etc.

Spine, Spriter, and Dragon Bones basically followed up as third-party versions of those proprietary tools. Now it's taken root as a definite style; even modern TV cartoons are using these setups, although they have more complex dolls with more keyframes. "Puppet" animation basically does the things that animators used to do by tracing model sheet drawings and it lets them go a lot faster, hence you can pull off 2D shows with detailed characters and still have it look crisp and polished.