I just recently upgraded to Sennheiser headphones. I wanted the best sound I could get with good noise isolation but NOT active noise cancelling, but cheap enough (~$130 on sale, IIRC) that I don't care too much if they get trashed.
Also, two of my cars don't have bluetooth. One is a 1991 ZR-1 Corvette. To go the bluetooth route, I'd have to install a 3rd-party head unit and gut the interior to run signal cables, amplifiers, and build custom speaker enclosures to fit where the BOSE amp+speaker assemblies are. So... 3.5mm-to-cassette adapter (or just listen to CDs) for that car. I'm not terribly worried about originality any more since a tree fell on the car... but I rather LIKE the stock appearance so when I restore it, I'm hoping to keep the stock head unit. I'll probably do a stealth install of speakers and amps at that point though, sacrificing the rear storage compartments - and possibly ABS since I used to disable ABS in that car anyhow.
The other is a Saab 9-3 that didn't come with bluetooth, so I use an AUX jack. I'd upgrade the head unit in a heartbeat, if it wouldn't result in a loss of functionality (car system alerts and sounds - everything including door and light alerts, turn indicators, etc. run through the stereo system). if a CAN bus interface which preserves these features is released I'd go for it... but since SAAB is long dead as an entity and there will never be any more Saabs built, the probability of such a device being released is near zero.
And, I use 3.5mm to RCA/phono jacks for playing content via my home stereo receiver. If you think I'm going to accept further degradation of the sound via bluetooth, you're nuts. It would be a waste of Klipsch speakers. I may have well stuck with the crappy JBLs I had previously (they were almost as bad as BOSE - no highs... although the JBLs produced decent lows, unlike BOSE.. why BOSE thinks their shit smells like a rose, no one knows...).
So, yeah... I use the headphone jack... a lot!
I also use bluetooth: in the Lesbaru (which DOES have bluetooth... and a surprisingly decent sound system!), and for hands-free phone calls in the above-mentioned vehicles.