I think using the unminified file is easier rather than having to minify it each time you change something. It's not like the composer doc will be a high trafic website needing this absolutely.
And having both the source and the minified script in the git repo is a bad idea anyway as it would require minifying each time you do a change to keep them in sync. Minifying should be a deployment task but this is overkill for the doc website IMO (even, Packagist does not minify its assets currently)