I used that approach too for a beginning frontend dev: see if they can get a solution to straight-forward problems, and ask them to explain it afterwards. They got all the time they needed, and a clean laptop with wifi. Two candidates came out well, two others didn't. That was a bit shocking, given the low bar.

But it won't cut it for a senior. Such people should be able to answer a wide range of questions, including some algorithm and data structure stuff. Not that they have to be able to code a min-max-heap from scratch, but they have to know what's out there, how to use it, and how to keep the overview of an entire project. That's not going to be evident from a coding interview.

So, horses for courses.