On flash media, bytes are just an arrangement of electrons trapped between a source and a drain. But you can't observe that directly. The only reason you understand that is knowledge piled on top of knowledge that someone else proved. Bitcoin is symbols all the way down.
Discussion
Lots of things which exist cannot be seen (if that's what you mean by "observe directly"), but they still exist. You could say the knowledge of their existence is really just a mental model or experience of simulacra, but that means everything is simulacra and nothing about bitcoin is special in that regard.
Bitcoin feels somehow uniquely simulacra. The closest you can physically get to viscerally "experiencing" bitcoin is physical miners. Outside of that, it is entirely people discussing symbols.