1) learning something new you might as well have something easier to learn 2) just becasue historicaly you had to use abreviations is not a handicap you have to impose upon yourself thesedays - especialy if your learning it from scratch and for educational aspects. 3) Sure you can use short TLA's instead of a longer version but for ease of reading and learning then something alot cleareer for the human without that over-comprimise you had with memory of computers is a artificial limitation. 4) realy not hard to run a substitution script to conver long to short and vice a versa - sed anyone!
We have all done assembly by hand and hand converted it, the compiler was a luxury for some back then and there small memory machines and even then you were not limited by the official shortcode versions of TLA's.
Thing is with hand converting is that you write something not maintainable on many levels, but as you said, you bent towards those lmitations as you had not alot of choice.
So if you want on say a Z80 write RETURN or the offical mnenoic of RET or go real hard code and just write C9 (using this example as my personal memory space seemed to of kept that one alive) then it was your choice. When you went to code it was C9h so converting RETURN or RET was something you did.
Least only op code that was standard across CPU's was NOP or "NO OPERATION" aka do nothing or 00h or 0 or 00000000, that was kinda portable and used by many for funky double-entry code padding etc. Though that was due to memory limitations and scary stuff to maintain, yet fun and rewarding to code. Apple early OS used that approach alot due to memory limitatons.
Heck of memory was such a limitation back then - explain COBOL becasue I can't, sadly still remember that as well :|.
