Super slow numeric property accessors - why is [0] / [1] access 110x slower than .x/.y?

accessors.ts

import { bench } from "@thi.ng/bench";
import { map, range } from "@thi.ng/transducers";

export class Vec2 {
    buf: Float32Array;

    constructor(buf: ArrayBuffer, off: number) {
        this.buf = new Float32Array(buf, off, 2);
    }

    get x() {
        return this.buf[0];
    }

    get y() {
        return this.buf[1];
    }

    set x(x: number) {
        this.buf[0] = x;
    }

    set y(y: number) {
        this.buf[1] = y;
    }

    get "0"() {
        return this.buf[0];
    }

    get "1"() {
        return this.buf[1];
    }

    set "0"(x: number) {
        this.buf[0] = x;
    }

    set "1"(y: number) {
        this.buf[1] = y;
    }
}

const N = 10000;

const buf = new Float32Array(N * 2).fill(1);
const pts = [...map((i) => new Vec2(buf.buffer, i * 8), range(N))];

const updateXY = () => {
    for (let i = 0; i < N; i++) {
        pts[i].x += 1;
        pts[i].y += 2;
    }
};

const updateXY2 = () => {
    for (let i = 0; i < N; i++) {
        pts[i]["x"] += 1;
        pts[i]["y"] += 2;
    }
};

const update01 = () => {
    for (let i = 0; i < N; i++) {
        pts[i][0] += 1;
        pts[i][1] += 2;
    }
};

bench(updateXY, 1000);
// 58ms

bench(updateXY2, 1000);
// 58ms

bench(update01, 1000);
// 6604ms