People have been yelling about this for the past couple of days, and I'm going to offer my opinion on the matter, even though no one asked.
If Figma is high fidelity, HTML/CSS/JS is ultra fidelity.
It's the final fidelity, and this is why there are teams that prefer this way of designing products. There is simply no better way of mocking a user experience, than the fidelity it's going to be eventually shipped in.
I personally was one of the designers who start in a tool like Figma, and finish in the code itself. This is how I designed this website. I can design some things in code, while I need to do some things in Figma first.
And this is the thing, we use Figma when we don't want to deal with the baggage of technology (using code), and want to focus on the UX challenge at hand. We agree to the abstraction so that we can think more clearly, move quicker, and cover more ground.
There are designers who don't have even the faintest bit of interest in using code. This is fine. Also, there are designers who are perfectly comfortable going in with code from day one. This is also fine.
See, when you work directly in code you are solving multiple problems at the same time. You are designing something at all viewport sizes at once. You are working around performance issues, and browser bugs. You are writing new code for styling and behavior purposes. You are making decisions regarding motion and animation, etc.
There's a reason 37signals' products have a certain aesthetic to them: they are designed in HTML/CSS/JS, and they reflect that. It's too much to do at once, so you embrace the simplicity as an aesthetic which gives you an illusion of fast progress.
If you tell me you don't have to do all these things at once, well than it's not fast anymore. You can tell me that there are frameworks which will enable these things out of the box, and I'll tell you have fun designing within the boundaries of that particular framework. And I'm not opposed to frameworks, just as long as everyone is aware of their limitations, and the cost of overcoming them.
Pick the right tool for the job, that's the answer. And stop making bold statements which come with great consequences to younger designers foolish enough to listen to you.
In this week's “Proof of Concept” newsletter, David Hoang reflects on this recent debate, but there are many other excellent takes in it, so I suggest adding it to you reading list.