Haven't seen A5 in the wild but I suppose it could be useful as a initial "Let's setup a connection" where endianness is unknown. Assuming the next thing that is exchanged is an endian negotiation.

Learning hardware just for the sake of it is tough to keep motivated and perhaps you would never use the skills you learn? Hardware adds a tougher level to debugging - but software experience gives you a fantastic start - a logical mind and rational drilling down.

If you can fix your car you have the skills to start on electronics!

A lot of skilled people grew up through the hardware generations e.g. I began learning basic electronics because on an Apple ][ everything was simpler and we were all at the same stage. My first job was writing low level serial driver code and regularly dealing with serial devices (e.g. on PC). Our modern context is just not the same. The internet is hard to learn from. It is difficult to write good articles to help - the experienced like me just know a huge variety of implicitly learned knowledge.

I suggest you concentrate on a useful or fun outcome - I believe it's good life practice (and good engineering) to stay focused on the outcome and not get too side-tracked by explicitly trying to learn. We implicitly learn just by doing!

I'd like to think that this is a comment on the ease of fixing cars, rather than a comment about how fixing cars is basically embedded hardware/software dev....

i was sending pixel data out from an Arduino (ESP32 really but using Arduino IDE) to a bunch of shift registers that seemed to be 74x595 (but couldnt know for sure) to resurrect an LED display for a local art project, and reading the data coming back out from the last register let me know I was at least getting back what I was putting in, which helped me troubleshoot a few wire length and speed/stability issues

to get started with electronics and hardware in general, I wrote a short tutorial: https://news.ycombinator.com/item?id=35116705