What problem does this feature solve?

Reduce the render events of the child components, the slots in my child components do not actually trigger any changes。

代码结构

import { defineComponent, reactive } from "vue";
import moment from "moment";
import headerBox from "@/components/header";
import card from "@/components/card";
import startdevice from "./start_device";
import operation_warm from "./operation_warm";

const staticData = {
  weekcn: ["一", "二", "三", "四", "五", "六", "日"],
};

const data = reactive({
  time: moment(),
});
export default defineComponent({
  components: { headerBox, card, runLog, startdevice, operation_warm },
  created() {
    this.getCdate();
  },
  methods: {
    getCdate() {
      setInterval(() => {
        data.time = moment();
      }, 1000);
    },
  },
  render() {
    return (
      <div>
        <headerBox />
        <div class="view_body">
          <div class="top_box title">
              {data.time.format("YYYY年MM月DD日")}
              <div class="time">{data.time.format("HH:mm:ss")}</div>
              星起{staticData.weekcn[data.time.isoWeekday() - 1]}
          </div>

          <div class="cards-box">
            <card
              class="left_card"
              title="设备启动 "
              vSlots={{
                body: <startdevice />,
              }}
            />
          </div>
        </div>
      </div>
    );
  },
});

Always provide a repro when reporting a bug and please, write the issue in English so more people can help