There is a particular reason: Users are bad about keeping their servers up-to-date.
Try to distribute a program without an embedded CA bundle to any number of users, and after a week you will surrender due to the bug reports you receive because users are running 5+ year old system CA bundles, which are not sufficient for connecting to some of the most popular API endpoints out there.
Try to distribute a program without an embedded CA bundle to any number of users, and after a week you will surrender due to the bug reports you receive because users are running 5+ year old system CA bundles, which are not sufficient for connecting to some of the most popular API endpoints out there.