I mean by useless is it's so slow you can't make games or even big projects for GUI, only you can do is AI/ML, Data Science, and basic stuff. I think Rust is better because of its speed and language capabilities?
Forth is powerful while still being very easy to interpret. This makes it a great bootstrapping step.
It's also used as a scripting language in some embedded system, it might be telescopes but I'm not sure. While forth wouldn't be my first choice there, I don't want to be able to crashed the device because I have hot swapped in a binary, compiled with the wrong flags.