Sensible defaults

By default, a native WAAPI animation requires a duration to be set, won't have any easing applied, and more annoyingly, won't persist its final value, letting the user to take care of setting the final styles manually after the animation completes.
Anime.js simplifies all that by making sure the animation state is preserved after the animation completes, and uses the same default duration and delay as the JS animate() method.

Syntax comparison

Anime.js

waapi.animate('.circle', { translate: '100px' });

WAAPI equivalent

const $el = document.querySelector('.circle');

$el.animate({ translate: '100px' }, {
  duration: 1000,
  easing: 'ease-out',
}).finished.then(() => {
  $el.style.translate = '100px';
});