The original link says: "This method is not the most efficient way of fetching and instantiating wasm modules. If at all possible, you should use the newer WebAssembly.instantiateStreaming() method instead, which fetches, compiles, and instantiates a module all in one step, directly from the raw bytecode, so doesn't require conversion to an ArrayBuffer."
Summary
The original link says: "This method is not the most efficient way of fetching and instantiating wasm modules. If at all possible, you should use the newer WebAssembly.instantiateStreaming() method instead, which fetches, compiles, and instantiates a module all in one step, directly from the raw bytecode, so doesn't require conversion to an ArrayBuffer."