I understand that this is the easiest way to include generated artifacts in composer packages as it rely only on sources repos, but I really don't like to commit generated assets in the VCS as it causes a lot of problems when merging and applying patches. This is an overall very bad practice.
In my quest to find a solution to this problem, I found Asset Packagist, which is kind of a proxy for Composer to install NPM packages. It seems quite interesting and I wonder if anyone here has already tried to use it.
From what I understand, it can be used independently by each packages so nobody will be forced to use it. I will probably experiment with it in the next few days.