I think it's useful to know whether an interviewee who has driven into your place of business is serious enough to spend 30 mins learning your platform.
It's fair if the website has useful content. I've been pinged before for not researching the company after their website basically said "we specialize in absolutely everything".
I think it's useful to know whether an interviewee who has driven into your place of business is serious enough to spend 30 mins learning your platform.