I highly doubt it's useful these days on general purpose computers, where even the very smallest ones can easily implement C (or better) or even run a whole operating system like Zephyr or Yocto.
However if you're creating your own computer from scratch or have other artificial constraints (like it needs to fit into a boot sector[1]), and if you want to really understand precisely how your language works down to the lowest level detail while still having high-ish level constructs, then Forth is the ideal small language for that.
However if you're creating your own computer from scratch or have other artificial constraints (like it needs to fit into a boot sector[1]), and if you want to really understand precisely how your language works down to the lowest level detail while still having high-ish level constructs, then Forth is the ideal small language for that.
[1] https://github.com/cesarblum/sectorforth