It's higher fidelity than 320 kbps. Not remotely higher fidelity than FM or CD quality audio. But I've A/B tested songs I know inside and out on the same equipment using both vinyl and 320 kbps mp3 and I can hear the difference night and day.
But the main reason I listen to it is not that it's better than Spotify, but that it's a physically beautiful medium with artwork and is still high quality while promoting active, intimate listening.
No it's not. SNR is at best 65dB, low frequencies go through processing before getting cut to account for limitations of the medium and channel separation is less than 30dB. Furthermore, there's wow, flutter and rumble. You also have issues with RIAA equalization (many preamps STILL can't get that right) and cartridge loading, that end up affecting high frequency response. The latter is also affected by stylus and record wear.
With vinyl being such a technically flawed medium, ofcourse you could A/B between that and a high bitrate MP3 file that most probably is transparent to a lossless source. MP3 reaches transparency at lower bitrates, as has been proven by ABX (not A/B, those are useless from a scientific perspective) tests conducted in many communities like Hydrogen Audio.
Was that MP3 encoded from audio ripped from the vinyl (with a good ADC)? ABX tests show that 320kbps MP3 is usually transparent, so for it to be "night and day" suggests the vinyl had better mastering. It's not always the case, but vinyl is sometimes mastered with higher dynamic range than the digital versions.
Vinyl seems higher quality because it's such an unforgiving medium. The mastering has to be done well or it'll sound terrible. The MP3, CD, and vinyl are not necessarily done by the same person, or someone with equal skill in each. FM has someone in a sound booth who knows what they're doing.
But the main reason I listen to it is not that it's better than Spotify, but that it's a physically beautiful medium with artwork and is still high quality while promoting active, intimate listening.