Probably same reason as me, the taboo of using them scares many people off them. Plus all the other effects they have like arch clearance ect. is another off putting part about them.
I know that a 3/5mm spacer is nothing but still... Just don't like the idea of using them if I don't have to.
I agree, if you don't have to use them then its best not to. But generally 95% of all BBKs would need spacers, so some compromise is needed.
Spacers are completely fine. All my cars have ran spacers and I've had zero issues whatsoever. My rocco has them on all 4 corners.
Otherwise you'll need to look at changing wheels for ones which give more clearance.
Mk2 cupra twin-5 spoke are a good OEM-ish option. But more expensive than spacers ....