Story time. I interviewed for a job at posthog. I knew that I really loved their communication style. But I hadn't used their product and didn't know a ton about them except that their writing is fantastic.
The 'product for engineers' focus that they is cool but when I had an interview, it was clear that I wasn't a 'product for engineering' person.
When they proposed the Super Day. I was like, I'm not sure because it's awesome to get paid for a day, but it's also not an unstressful event. And I sort of said I had some more questions before we moved on to the Super Day.
And they basically just said: we don't think it's going to work out. It was actually a pretty positive experience. I think that they correctly assessed the situation pretty quickly and my hesitation was a real signal to them.
(This is my recollection - I could have the details wrong.)
But yeah, super day is a day of very structured work in the role that they setup. And its paid.