VisibilityTagHelper.cs

[HtmlTargetElement("div")]
public class VisibilityTagHelper : TagHelper
{
    public bool IsVisible { get; set; } = true;

    public override void Process(TagHelperContext context, TagHelperOutput output)
    {
        if (!IsVisible)
            output.SuppressOutput();

        base.Process(context, output);
    }

    public override Task ProcessAsync(TagHelperContext context, TagHelperOutput output)
    {
        if (!IsVisible)
            output.SuppressOutput();

        return base.ProcessAsync(context, output);
    }
}

Allows you to use:

<div is-visible="@Model.LoggedIn">
<p>For logged in eyes only</p>
</div>

instead of

@if (Model.LoggedIn)
{
<p>For logged in eyes only</p>
}