Because we only got to do it during the 8 bit era, there were tons of books and magazine listings to learn it, and for many of us it was the only way to get software.

16 bit home computers already had structured BASIC compilers, producing native code, for example I learned Turbo Basic in 1990.

Here is how it looked like,

https://archive.org/details/bitsavers_borlandBorsHandbook198...

Amiga demoscene was presented with AMOS.

Just to cite those which I had more experience with.