Considering this has been in the news for 10 years and pretty much no one does it, not even a weird sub community, we can safely say this is not a legitimate sleeping pattern for humans.
Ever since working from home during the pandemic sleeping from like 2am-6am at night and like 4pm-6pm has become pretty common for me. Not sure if that counts as "biphasic" or just a very long nap but definitely seems fine to me.
Speak for yourself. I personally do it, it's fantastic. But it does get me a little out of sync with the rest of the world, but with time differences etc. it's not a big deal.
I'm sure a LOT of people do it, and if you turn off your alarm clock and having to get up at x time, and going to sleep at y time, to be 'refreshed' etc, you'd notice the benefit yourself.
Just sleep when you're tired, eat when you're hungry. Trying to have rigid rules around all this does more to damage peoples health than anything else.
My parents (mid 50s) have been doing this for 5-10 years. It just kind of came about naturally with their workdays starting late and them being night owls, and they leaned into it. It's weird enough that I imagine many of the people who do this don't really talk about it with strangers.