为什么 syncUserActivedAt () 要写成实例方法，而不是类方法？

教程中
app/Console/Commands/SyncUserActivedAt.php

<?php

namespace App\Console\Commands;

use Illuminate\Console\Command;
use App\Models\User;

class SyncUserActivedAt extends Command
{
    protected $signature = 'larabbs:sync-user-actived-at';
    protected $description = '将用户最后登录时间从 Redis 同步到数据库中';

    public function handle(User $user)
    {
        $user->syncUserActivedAt();//定义成类方法，然后User::syncUserActivedAt();这样调用不好么？
        $this->info("同步成功！");
    }
}