As someone with a hardware background, I'll throw in my $0.02. The schematic capture elements to connect up large blocks of HDL with a ton of I/O going everywhere are one of the few applications of visual programming that I like. Once you get past defining the block behaviors in HDL, instantiation can become tedious and error-prone in text, since the tools all kinda suck with very little hinting or argument checking, and the modules can and regularly do have dozens of I/O arguments. Instead, it's often very easy to map the module inputs to schematic-level wires, particularly in situations where large buses can be combined into single fat lines, I/O types can be visually distinguished, etc. IDE keyboard shortcuts also make these signals easy to follow and trace as they pass through hierarchical organization of blocks, all the way down to transistor-level implementations in many cases.
I've also always had an admiration for the Falstad circuit simulation tool[0], as the only SPICE-like simulator that visually depicts magnitude of voltages and currents during simulation (and not just on graphs). I reach for it once in a while when I need to do something a bit bigger than I can trivially fit in my head, but not so complex that I feel compelled to fight a more powerful but significantly shittier to work with IDE to extract an answer.
Schematics work really well for capturing information that's independent of time, like physical connections or common simple functions (summers, comparators, etc). Diagrams with time included sacrifice a dimension to show sequential progress, which is fine for things that have very little changing state attached or where query/response is highly predictable. Sometimes, animation helps restore the lost dimension for systems with time-evolution. But beyond trivial things that fit on an A4 sheet, I'd rather represent time-evolution of system state with timing diagrams. I don't think there's many analogous situations in typical programming applications that call for timing diagrams, but they are absolutely foundational for digital logic applications and low-level hardware drivers.
[0]: https://www.falstad.com/circuit/
I've also always had an admiration for the Falstad circuit simulation tool[0], as the only SPICE-like simulator that visually depicts magnitude of voltages and currents during simulation (and not just on graphs). I reach for it once in a while when I need to do something a bit bigger than I can trivially fit in my head, but not so complex that I feel compelled to fight a more powerful but significantly shittier to work with IDE to extract an answer.
Schematics work really well for capturing information that's independent of time, like physical connections or common simple functions (summers, comparators, etc). Diagrams with time included sacrifice a dimension to show sequential progress, which is fine for things that have very little changing state attached or where query/response is highly predictable. Sometimes, animation helps restore the lost dimension for systems with time-evolution. But beyond trivial things that fit on an A4 sheet, I'd rather represent time-evolution of system state with timing diagrams. I don't think there's many analogous situations in typical programming applications that call for timing diagrams, but they are absolutely foundational for digital logic applications and low-level hardware drivers.
[0]: https://www.falstad.com/circuit/