Instruction Set Architecture. That which defines the encoding of opcodes to actual functional units/instructions of an underlying machine. You've got a valid

Instruction Set Architecture. That which defines the encoding of opcodes to actual functional units/instructions of an underlying machine. You've got a valid question. The answer is: Because you apparently have a WASM environment, and not a C++ or rust environment. There is no virtue to any one thing over another. It's all, what you have to work with at the time.