According to https://github.com/yiisoft/yii2/issues/14862
One of the main issues with this approach is that bower is deprecated #14297, and projects start dropping bower support (eg. https://news.ycombinator.com/item?id=10891324, lodash/lodash#2206 (comment), chartjs/Chart.js#3081 {they brought it back, but still...}).
While this currently does not affect "near-core" packages, like jquery or bootstrap, there should be a safe migration path to npm in planning.
The next major version of Composer Asset Plugin is so different, but also incompatible with the current version, that it became a new project named Foxy.
Foxy is the new way to manage the assets of PHP libraries, because it works nativelly with all the features of NPM or Yarn. However, this plugin will continue to be maintained by the community, without having new features.
See to see more details : https://github.com/fxpio/foxy/blob/master/Resources/doc/faqs.md