You’re either misremembering things or talking about an era after Bluetooth had already taken off.

In the days before Bluetooth, transferring MP3s over IR took multiple minutes, even on high end (for the time) handsets.

And the fact that you needed to keep line of sight during the whole process meant your phone couldn’t be used that whole time. Which was a real pain in the arse if you got a text message or phone call while trying to transfer a file.

IR was really more designed for swapping contacts. In fact that’s exactly how BlackBerry (or was it Palm?) marketed IR on their device: a convenient way to swap contact details. But you’re talking about a few KB vs several MBs for an MP3.

The tech has definitely moved on since. But then so has Bluetooth, WiFi and GSM et al too.