Different devices may not read the files the way that you want them to but you can upload just about anything.
THESE ARE NOT CDs.
There is no standard.
The way a machine accesses the files on the USB will not be consistent.
For example, you can have a perfectly fine video file on a high quality USB...but if the computer can’t play that type of video file, it simply won’t play. That’s not because of anything anybody did wrong. The end user simply isn’t equipped. Luckily, with today’s technology, it’s pretty rare to encounter issues.
For audio file playback in cars, MP3 files are more universally recognized.