A class file contains a bunch of commands/opcodes/data intended to be read by the JVM which, when viewed by humans is mostly just a huge bunch of numbers & embedded senseless text.
The reason why you need to disassemble to read this is because the disassembler organizes it in a way that makes sense to humans and substitutes the numbers for their textual commands (e.g. textual versions of the opcodes like aload instead of \19 or goto instead of \A7) which make more sense to humans.
