I went through the same argument a few years ago. I got the "rates" for hiring an identical aircraft from the local flying club. Over the year, we paid (in total) very slightly more for the "group" aircraft than we would have paid for the club one.
The point made was that the BIK was zero or negative.
Whether that argument would hold up if used for the first time now, I don't know.
Cars are a specific and different case. The Revenue (or the Chancellor or someone) wanted to stop companies providing cars, so they came out with some very inequitable rules, which not surprisingly killed the Company Car business. Probably also helped the demise of the UK car industry.