bit-serial cpus were common in the 01950s and still sold up to the 01970s; the lgp-30, the pdp-8/s, and the rca 1802 were three historically significant examples. the bit-serial approach cuts your hardware complexity by about half while cutting your performance by, typically, about a factor of 20. for a couple of decades, computers that weren't bit-serial were described as 'parallel' even if they only ran one instruction at a time (you can find this in early intel literature)

probably 32 bits is wider than optimal for this kind of thing but not having to write your own c compiler and assembler toolchain is worth a lot, especially if, as in serv, your cpu doesn't try to trap on illegal instructions

even if you're writing asm, risc-v asm requires a lot less bending over backwards than, say, 8051 or 6502 or pic or even avr, and you don't have to worry about overflow much. it's not quite as pseudocody as i386 assembly tho

there are an awful lot of control tasks where one frame of doom every four seconds is much more performance than you actually need, like kindgren's examples in this talk: ddr memory initialization, logging, slow sensor data aggregation, and control planes; i'd add pid control, motor control waveform generation, and guitar pedals and other audio dsp applications (maybe using the serv core to orchestrate the activities of a larger dsp core, similar to how the s1 mp3 used a z80)

wrt the question about educational applications, femtorv32 is probably an easier implementation of risc-v to understand; it's a lot less verilog and a lot more straightforward

— ⁂ —

for videos like this that are mostly slides and somebody talking, if you're interested in the verbal information and not the pretty face, i recommend

    yt-dlp --write-auto-sub --sub-lang en,es -f '[height<800]' https://www.youtube.com/watch?v=GSHasXHvZaQ

(or possibly even just downloading the .vtt files without the video at all; it is unfortunate that youtube doesn't have an 0.5 fps 640×480 option for things like this)

and then

    devtt.py < SERV：\ 32-bit\ is\ the\ New\ 8-bit\ -\ Olof\ Kindgren\,\ Qamcom\ \[GSHasXHvZaQ\].en.vtt |
        less

where devtt.py is http://canonical.org/~kragen/sw/dev3/devtt.py or equivalent (i can't have been the first person to want this, and probably someone has written a better version)

the transcript is only 2130 words and so reading it only takes about 6 minutes, while the video is 21 minutes

the transcript has a lot of errors but is adequate