How does that prevent you from using your personal laptop for a job interview?

It would never occur to me to use an employer's hardware for such a purpose. It seems absurdly lazy, but I know that not everyone's life works like mine, so I would like to understand why this would be a real problem for people.

If you work from the office, and they have tight security, they might frown upon bringing personal devices to connect to the internal network.

Also, some people might not have dev environments set up on their personal devices. Heck, a lot of people only use the internet through their smartphone, when they're not at work.

I had a really bad meeting one day that became the straw that broke the camel's back. When I went back to my desk, I saw an interesting job posting. I immediately fired up the company's copy of Word to draft up a resume, and used the company computer to send the email from my personal account. Less than a month later, I was working for the new company. It was done intentionally. I almost sent the resume via company email, but I really wanted to ensure I could access any response.