From the "Disadvantages" section of your first link:
"No technology is magical, every transition comes with disadvantages. An Isolate-based system can’t run arbitrary compiled code. Process-level isolation allows your Lambda to spin up any binary it might need. In an Isolate universe you have to either write your code in Javascript (we use a lot of TypeScript), or a language which targets WebAssembly like Go or Rust."
"If you can’t recompile your processes, you can’t run them in an Isolate. This might mean Isolate-based Serverless is only for newer, more modern, applications in the immediate future. It also might mean legacy applications get only their most latency-sensitive components moved into an Isolate initially. The community may also find new and better ways to transpile existing applications into WebAssembly, rendering the issue moot."
From the "Disadvantages" section of your first link:
"No technology is magical, every transition comes with disadvantages. An Isolate-based system can’t run arbitrary compiled code. Process-level isolation allows your Lambda to spin up any binary it might need. In an Isolate universe you have to either write your code in Javascript (we use a lot of TypeScript), or a language which targets WebAssembly like Go or Rust."
"If you can’t recompile your processes, you can’t run them in an Isolate. This might mean Isolate-based Serverless is only for newer, more modern, applications in the immediate future. It also might mean legacy applications get only their most latency-sensitive components moved into an Isolate initially. The community may also find new and better ways to transpile existing applications into WebAssembly, rendering the issue moot."