I don't know what's worse, the 45 day trial or the "congratulations! You've jumped through 3 fire hoops! Now you have the chance to come spend a full day being interviewed by 10 different people!" stuff.
A lot of companies have probation periods though.
You're on a trial at every single company anyway, they just aren't as up front about it.
I understand the problem for Buffer, but this isn't the solution.
I've heard of companies who offer people to consult on weekends for a predetermined total number of hours to accomplish much the same outcome. Annoying, but I'll play ball.
...but really. I seriously doubt any high-end dev talent is willing to take such risks. And if you think this hiring strategy would be successful in attracting high-end dev talent that really cares about Buffer, well you haven't examined the hiring market lately and are likely high off your own supply.