I started my career being pretty terrible with interviews for reasons pretty well encapsulated in Thomas' article -- general nervousness, social anxiety, lack of confidence (in retrospect, I believe this was primarily an impostor syndrome issue).

I've gotten better at it with age, but the improvement in my interviewing skill is completely unrelated to my improvement in programming skill, though I believe both continue to improve still into my early 40s.

Speaking on behalf of younger me, and probably others like younger me:

Doing the work on a computer is scarcely better than coding on a whiteboard, and in some ways it is worse. It isn't my computer. It is set up all different, it would take me hours to set it up like mine, the keyboard is all weird, what the fuck is the ctrl key doing over there, fucking Lenovos, all of these are trivial differences in isolation but in aggregate they make the work seem just as foreign as doing it on a whiteboard especially because I already feel like I am "under the gun".

Also (and by far most importantly and relevant even if I had brought my own computer in): I'm being "watched". Even if you aren't actively watching me (or rather, younger me), I am effectively being watched if I'm sitting in some room at your company banging out code. I'm all up in my head about how this is taking too long, how long ago did I start, how long are they expecting this to take, etc, I never get anywhere even close to the "flow" that I commonly get into when I am doing real work, the whole experience is just completely unlike the experience I have when doing actual work and feels like torture.

And then lastly (drifting somewhat out of scope of both the original blogpostand Thomas' blogpost) another issue I've always had with these types of interviews is that I'm somewhat of a subconscious worker, in the sense that when I am presented with a thorny technical problem the way I often best deal with it is by not really thinking about it (consciously), but rather going for a walk, taking a nap or just otherwise zoning out and letting the solution sort of materialize out of my subconscious. This is obviously completely incompatible with any kind of traditional programming interview, where the interviewer is almost obsessively looking to "see the work" in how you're thinking about the problem and I can't just ask them to let me go take a walk for 15 minutes and get back to them with the solution they're looking for (generally - I'm sure some will respond saying they'd be okay with this, but practically speaking we all know it wouldn't fly in the vast majority of interviews). An extremely common occurrence for me back during the time when I did not interview very well is I'd be driving back from the interview and would just suddenly have completely fantastic answers for all of the questions that didn't go very well on-site, a technical interview version of l'esprit de l'escalier.

Having said all of this, I'm not one to suggest anyone who interviews in any specific way is objectively wrong (for their own needs). If whatever system you use generates enough hires to get the work done, then so be it; but I can really relate to a lot of the problems highlighted in Thomas' article, so at the very least I hope people interviewing with more traditional methods than he has been working towards realize they are certainly filtering out some really great hires (which is maybe okay for them, but like Thomas I believe ultimately bad for the industry if we continue with what we have now as the standard).