[C#] AttributeMetadata "IsSearchable" always false

I'm trying to access AttributeMetadata using Microsoft.Xrm.Tooling.Connector (link) using the GetAllAttributesForEntity function.

var entityAttributes = client.GetAllAttributesForEntity("account");

foreach (var attribute in entityAttributes)
{
  // attribute.IsSearchable.Value is always false
}

However, it seems that the attribute "IsSearchable" (and perhaps other attributes, but our focus is on this) is always false, however, in CRM the attribute is set to Yes for most fields. Is there something I'm missing?