: MP4 files often use AAC (Advanced Audio Coding), which can provide higher audio fidelity than standard MP3s at the same bitrate. Web audio codec guide - Media | MDN

Most modern devices and operating systems support MP4 natively without additional software. : Double-click to open in Windows Media Player. macOS : Double-click to play via QuickTime Player.

It is common to confuse these two, but they serve different purposes: : Strictly an audio-only format.