Yes. My first serious program was done this way. At the start of the project (final year of EE degree, 1981) I didn't really understand what a program was, but I learned by studying the technical reference manual for the Intel 8085 CPU. It kind of seemed like magic, I can mold the functionality by storing codes in memory? Wow!

I figured out exactly what I wanted to do, wrote it out very carefully on paper, looked up all the hex codes, wrote those out very carefully, adjusted addresses etc. as needed. This took many hours spread over weeks. Then I entered the whole thing on the hex keyboard and display of a primitive development board each time I needed it, perhaps an hour or so each time (I think I only did it twice). It worked first time, because why wouldn't it if you were sufficiently meticulous about your work in a process that was very obviously very intolerant of the tiniest mistake?

I must admit my program (gather input information from some transducers, do some calculations, present some results) was likely somewhere between one and two orders of magnitude simpler than a complete Basic interpreter!

My first exposure was Commodore PET computers at the high school (I'm old). Nobody had home computers then, this stuff was crazy expensive, even a floppy disk (singular!) to save your work on the shared drive (on a dolly - it could be hotplugged) was >$20 in today's money. But what you could use all you want was the line printer (a CBM 2022) and its consumables. So at the end of whatever computer room time you could scrounge (lunch, who needs lunch?) you'd print off your 3-4 page epic program to continue coding and debugging with a pencil, on the long school bus ride. This does form "slow" habits. To this day I detest autocomplete, autoindent, syntax highlighters and the like. Never did hand assemble though.

There was a #hexcoders channel on IRC back in the 90s, admittedly very dead, and not just because octal is better for x86 code.