I feel the latter is an oftentimes overlooked part of car audio... Why would I need lossless audio quality in a car that, even if it's a well insulated barge like this, has a ton of road and engine noise. Doesn't make any sense. Also the speakers themselves won't be that great and, even if upgraded, will be awkwardly placed because reasons - so even if stationary, the result most probably won't suffer from the tunes being crammed through BT or other compression. ... Tesla does take it a bit too far with their 64kbit/s streams, thoughAudio quality is maybe not audiophile but a huge step up from the cassette, and definitely on eye level with FM radio. Which is good enough for drivetime music.
I installed a similar thing in my V70 with the same head unit back in the day. It was a different time though, the kit cost an arm and a leg and the handsfree and bluetooth modes sounded terrible. 30-pin to my iPhone was fine, though, which was what I used most of the time. I had the headunit out umpteen times and I lost one of the two screws into the depths of the center console somewhere under the shifter. It was never to be seen again, not even with a magnet.
The upside of driving the same car as everyone else is that the pen holder probably is readily available from any random boneyeard if you need a new one.
This is still my go-to solution for in car audio. Car cassette players are dirt cheap, don't look out of place in any of the cars I own and the sound quality is more limited by the speakers than the head unit/input device. I even have a bluetooth one which is handy for cassette players that eat the cassette entirely rather than leaving it sticking out. Somewhat annoyingly the player in the 740 doesn't like them though, the mechanism seems to be too stiff and it triggers the auto-reverse. So that has an FM transmitter, which is significantly worse.I remember that 3,5mm adapter cassettes were a big thing first when the Diskman and then when MP3 players popped up.