Testing Forth and ASM code snippets in the REPL before committing to them helps eliminate those nasty assumptions about what "should" work.
In the late 1980s I had a group of friends at Apple that included Smalltalk, Lisp, and FORTH programmers. We certainly found plenty of things to admire and attempt to steal from one another, and everyone accepted the basic goodness of building systems by engaging in conversation with them as they run.
Lisp and Smalltalk cross-pollenated each other more than each did with FORTH, but maybe Slava Pestov's Factor is a glimpse of what you get if FORTH is more in the mix.
I find it better to think of Forth as a clever Macro Assembly language for a two stack VM.
When used as designed, one does not actually program in Forth. You first write a tiny "language" and program the App in that.
Not a popular choice today.
Around the time that MacFrames morphed into SK8, Apple hired an arcade-game programmer named Dave Vronay to work on the SK8 graphics subsystem. When I first met him, he was over the moon about MCL and how great it was to write assembly code in a repl and run it right now.