Forth was invented around 1970 for controlling equipment in an astronomical observatory, running on a PDP-11, a 16-bit computer with up to 64 Kbytes of memory. Its heyday was the 1970s and 80s, when it was mostly used for small embedded systems on 8- or 16- bit processors with 8 kb -- 64 kb of memory. It was possible to run an entire Forth development system along with the application on these small targets without resorting to a bigger computer for cross-development.

The usual alternative to Forth on those systems was assembly language.

I was dropped into one such system after it failed after like 20 years and learned forth on the fly while managers breathed down my neck lol. Not a fun experience, and it took about 3X as long as I thought it would take, so Forth is not my favorite language, but I do see why it was useful at the time, and as an exercise in a way of thinking about languages rather than the mode I usually operate in c/c++/rust/little javascript