I saw two sentences in the document:
https://react.dev/reference/react/use#caveats
1. use re-renders the component after the data is resolved.
Question: Why is useMemo executed again when re-rendering? How to understand re-render here?
2. Promises created in Client Components are recreated on every render.
Question : How to understand this sentence

Demo : https://codesandbox.io/p/sandbox/react-dev-forked-8fpjhd?workspaceId=ws_HRgeaCc4c14UUVZk6sijk9

code:

import { use, Suspense, useMemo } from "react";
function generateRandomString(length) {
  let result = "";
  const characters =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";
  const charactersLength = characters.length;

  for (let i = 0; i < length; i++) {
    result += characters.charAt(Math.floor(Math.random() * charactersLength));
  }

  return result;
}
let prevPromise = null;
function Message({ messagePromise }) {
  
  if (!messagePromise) {
    return <p> messagePromise is null</p>;
  }
  console.log("render message ");
  console.log(
    "prevPromise",
    prevPromise,
    "messagePromise",
    messagePromise,
    prevPromise === messagePromise
  );
  prevPromise = messagePromise;
  const person = useMemo(() => {
    return {
      name: generateRandomString(4),
    };
  }, []);
  //The person's name has a different value every time you render. Why??
  console.log("person", person);
  const messageContent = use(messagePromise);
  console.log("after use messagePromise");
  return <p>Here is the message: {messageContent}</p>;
}