Sure, there are plenty of cases where visualization is helpful. But I see so many blog posts about it, and not much in the way of actual progress.

Take the card again. It's your example, after all. I cannot think of any way to use that to, say, write a small AI to play poker. I suppose I could see a use in a debugging situation for my 'hand' variable to display a little 5@ symbol (where @ is the suit symbol). But okay, let's think about that. What does it take to get that into the system?

No system 'knows' about cards. So I need a graphics designer to make a symbol for a card. I surely don't want an entire image of a card, because I have 20 other variables I am potentially interested in, which is why in this context a 5@ makes sense (like you would see in a bridge column in a newspaper). So somebody has to craft the art, we have to plug it into my dev sysstem, we need to coordinate it with the entire team, and so on. Then, it is still a very custom, one off solution. I use enums, you use ints, the python team is just using strings like "5H" - it goes on and on. I don't see a scalable solution here.

Well, I do see one scalable solution. It is called text. My debugger shows a textual depiction of my variable, and my wetware translates that. I'm a good reader, and I can quickly learn to read 54, "5H", FiveHearts as being the representation of that card. Will I visually "see" the value of a particular hand as quickly? Probably not, unless I'm working this code a lot. But I'll take that over firing up a graphics team and so on.

I do plenty of visualizations. It is a big reason for me using Python. If I want to write a Kalman filter, first thing I'm doing is firing up matplotlib to look at the results. But again, this is a custom process. I want to look at the noise, I want to look at the size of the kalman gain, I want to plot the filter output vs the covariance matrices, I want to.... program. Which I do textually, just fine, to generate the graphics I need.

I've dealt with data flow type things before. They are a royal pain. Oh, to start, it's great. Plop a few rectangles on the screen, connect with a few lines, and wow, you've designed a nand gate, or maybe a filter in matlab, or is it a video processing toolchain? Easy peasy. But when I need to start manipulating things programmatically it is suddenly a huge pain.

I am taking time out of writing an AI to categorize people based on what they are doing in a video (computer vision problem) to post this message. At a rudimentary level graphical display is great. It is certainly much easier for me to see my results displayed overlaid on the video, as opposed to trying to eyeball a JSON file or something. But to actually program this highly visual thing? I have never, ever heard anything but hand waving as to how I would do that in anything other than a textual way. I really don't think I would want to.

Anyway, scale things up in a way that I don't have to write so many matplotlib calls and you will have my attention. But I just haven't seen it. I've been programming since the early 80s, and graphical programming of some form or another has been touted as 'almost here'. Still haven't seen it, except in highly specialized disciplines, and I don't want to see it. "Pictures are worth a thousand words" because of compression. It's a PCA - distill a bunch of data down to a few dimensions. Sometimes I really want that, but not when programming, where all the data matters. I don't want a low order representation of my program.