In the past I used Bluetooth for keyboard and mouse when I connected the phone to a monitor. (I no longer do because the USB port on my L5 has broken down so badly that it can no longer maintain a DisplayPort Alt mode connection.)
I’ve never used Bluetooth for music or similar, it keeps stuttering horribly on my L5. No idea why it does that!
I’ve never used multimedia SMS either. Almost no one uses SMS or MMS in Germany. Signal barely works via the Electron app (and signal-cli), so that’s what I use for messaging. WhatsApp doesn’t work because I have no iOS or Android to tether it to.
I can’t use public transport apps, which is a shame because I live in a city center where I depend on public transport. I download my public transport ticket from a private API once a month via curl.
For file transfer, I mostly use rsync, Git, or Unison.
Banking only works thanks to a dedicated bank card reader. [1]