You'd be amazed just how much you can learn about someone's actual skills and experience (or lack thereof) through long-form discussion. I think we don't truly talk enough in our currently broken interview process.
My current job was also behavioral where I am a staff architect at a 3rd party company and it does require coding. As an interviewer, I also only do behavioral interviews. But let’s be realistic, it doesn’t take much to be a competent enterprise dev or even an enterprise architect.
The type of hard problems that BigTech has to solve is completely different. While I would never have trusted any developer I ever met at AWS within 100 feet of a customer, they also shouldn’t let me within 100 feet of the code that runs any of the AWS services.
Even at my medium size consulting company we have a 0.4% application/offer rate. Can you imagine what it is at BigTech? How do you filter just by talking to someone?