[1] https://cuis.st/
Cuis Smalltalk and related implementations are rather self-contained systems to the point they seemed walled off from the rest of the system, making it difficult to develop Smalltalk programs using external tools.
However, there's something compelling about the idea of a Smalltalk (or Lisp) OS running on bare hardware, where everything runs in a single address space. I've been thinking about this for a few years, but I haven't had time to pursue these ideas. Some ideas from the 1994 paper "Sharing and Protection in a Single-Address-Space Operating System" (https://homes.cs.washington.edu/~levy/opal.pdf) could be applicable to add some security to a Smalltalk OS.
It isn't the full thing, but apparently it is very hard to get mainstream interest in such approaches.
Naturally this is not the same as using Smalltalk, or the other three Xerox PARC siblings, only partially.
There were some efforts to run Squeak on the Raspberry PI I think, but eventually they runned out of steam.
https://hackaday.com/2020/07/12/making-smalltalk-on-a-raspbe...
The project you linked to recreated the original Xerox Smalltalk-80 on the Pi. It has a rather limited scope so I don't know if they ran out of steam or simply reached the end.
I guess that by "ordinary programs" you mean command-line TUI programs.
Being able to explore and inspect helps whether you are writing GUI or TUI.
When you write Smalltalk code with a Smalltalk IDE, your actions have an implicit context. If you write Smalltalk code with a plain text editor, you must provide that missing context. Something like the fileOut format —
!BenchmarksGame class methodsFor: 'initialize-release'!