我假设onclick事件被视为与文档交互，因此不确定抛出自动播放错误的原因

未捕获（promise中）NotAllowedError:play（）失败，因为用户没有首先与文档交互。

const playbtn = document.getElementById('playbtn');
const player = document.getElementById('video-player');
const vimeoPlayer = new Vimeo.Player(player);
playbtn.onclick = function() {
  playbtn.style.display = "none";
  vimeoPlayer.play();
}
vimeoPlayer.on('pause', function() {
  playbtn.style.display = "block";
});
vimeoPlayer.on('play', function() {
  playbtn.style.display = "none";
});

i {
  position: absolute;
  color: white;
}
.fa-play-circle {
        display: block;
        position: absolute;
        left: 50%;
        top: 50%;
        font-size: 20rem;
        -webkit-transform:  translateX(-50%, -50%);
        -moz-transform:     translate(-50%, -50%);
        -ms-transform:      translate(-50%, -50%);
        -o-transform:       translate(-50%, -50%);
        transform:          translate(-50%, -50%);
        z-index: 2;
        color: white;
        color: rgba(255,255,255,0.75);
}

<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.2/css/all.css" integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr" crossorigin="anonymous">
<script src="https://player.vimeo.com/api/player.js"></script>

<div id="video-outer-full">
  <div id="video-inner">
    <i class="far fa-play-circle" id="playbtn"></i>
    <iframe id="video-player" class="video" width="560" height="315" src="https://player.vimeo.com/video/309741585" frameborder="0" webkitallowfullscreen mozallowfullscreen allowfullscreen></iframe>
  </div>
</div>