I have a channel list and looking at it all the url's link to mp3 streams, this is fine for me, the quality is very good especially listening through a wired headset or over BLE. Occasionally if the connection gets flaky at my end or the server end, packets will get dropped and I get a "click" every so often but usually I can listen for hours without an issue.
I've looked at PSRAM briefly but not implemented it with anything yet, maybe your example is using it for the stream buffer, I created my own ring buffer there was plenty of room for it on the nano.