Hi
For me this thread illustrates two things that are conflated:
- The audience as serious coders vs people (like me) who want to get into dataviz but are not completely competent in coding, and the already stated issue that
- “tying the D3 documentation too tightly to Observable” is a problem.
That’s the TL;DR.
I am a complete newbie to all things coding related. I came at this from a completely unrelated field (biology). I have tried for a few years, unsuccessfully, to learn D3 because I think it is the best way to visualise material flows (for urban metabolism, nutrient management and that sort of thing, that I used to research). I love Observable, because it finally allowed to me to see step by step all the things I was doing wrong, because it works in cells. I was doing sooooo many things wrong that the standard tutorials and ways to learn was not helping - you know when you misspell something so badly that spell checker can’t even help? That was me. I am now becoming much better at this, and starting to learn JavaScript and slowly getting back to the more pure coding stuff. I think this is a great platform, but you need to know why it exists for. I even think I can tackle Python again after this. I know these things are powerful but they were really just too much for me before. My main problem at the moment is that I get too distracted trying new things with my newfound power.
I don’t think Observable exists for serious coders. I think it is a nice notebook for some serious coders who want to quickly try something, or share a tutorial or example type of thing. If you “already know what interactive data visualization means and have already developed websites” then, as I understand it, Observable is not primarily for you. I consider Observable to be “a library as the go-to tool for all visualisation needs,” BUT mainly for non-coding people.
For me data viz is going to be fundamentally frustrating and have a steep learning curve, because of the multidisciplinary nature of it. Journalism, data wrangling, statistics, story telling, graphic design, etc etc etc. So assuming that Observable, that exists to help with this, won’t have some steep learning curve somewhere, is naive and unfair. It’s also very new, so things will get better. Be kinder with your feedback.
I think dataviz is only going to be a bigger part of how we work and report, and Observable is helping to grow that competency base. I think it is a good platform for newcomers to code in general, rather than newcomers from code to D3, because it “allows people to experiment quickly and also write good documentation” and the rest of j-pb’s reply.
What I am trying to do is play in Observable, and then export the thing I created as a picture. I am most excited by the interactive, animation stuff, and I think I’ll have to learn a bit more about how to do that and export it to run on my website, for example. But as something to show to my colleagues / deliver to future clients to put excellently informative custom images in their reports, Observable is a win.
Lastly, this thread itself was very valuable, thank you. I realised there are things I struggle with that is not my incompetence but the D3-observable tightness, for example 
And I learnt I can download the raw code!