Issue with `display:inline-block` CSS property

Question

I have made recently one answer to another user about a generic method for JQuery::slideUp() sequentially multiple items. If you want a reference, you can check it here:

slide up elements in a sequential order

After come to a solution the OP asked me about an initial jumping effect that you can observe on the next code:

$('button').on('click', function()
{
    close_all($(".block"));
});

function close_all(elements, idx=0)
{
    if (idx >= elements.length)
        return;

    let cb = () => close_all(elements, idx + 1);    
    elements.eq(idx).slideUp(2000, cb);
}

.block {
  display: inline-block;
  width:14%;
  background:gold;
  margin:0 9px;
}

#block1{
  height:54px;
}

#block2{
  height:25px;
}

#block3{
  height:72px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div class='block' id='block1'>BLOCK 1</div>
<div class='block' id='block2'>BLOCK 2</div>
<div class='block' id='block3'>BLOCK 3</div>
<button>CLICK</button>

After digging a little about it, I have come that this is related to display:inline-block property he has over the .block elements. For what I have read so far (I'm not experimented on CSS) this property it a sort of replacement for float:left. So I decided to change the style to use float:left instead of display:inline-block and the issue disappear. You can check it on next code:

$('button').on('click', function()
{
    close_all($(".block"));
});

function close_all(elements, idx=0)
{
    if (idx >= elements.length)
        return;

    let cb = () => close_all(elements, idx + 1);    
    elements.eq(idx).slideUp(2000, cb);
}

.block {
  float: left;
  width:14%;
  background:gold;
  margin:0 9px;
}

#block1{
  height:54px;
}

#block2{
  height:25px;
}

#block3{
  height:72px;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div class='block' id='block1'>BLOCK 1</div>
<div class='block' id='block2'>BLOCK 2</div>
<div class='block' id='block3'>BLOCK 3</div>
<button>CLICK</button>

Anyone has idea why the issue appears when we use display:inline-block?