The option to have a placeholder in a dropdown is great! It saves us from needing to add those manually. I’m probably pretty late to realizing that feature is there, but now that I have used it, it would be really nice to have a checkbox in the properties to hide the placeholder from the actual dropdown list. In HTML that just adds the hidden attribute to the option element for the placeholder.
The idea is that the placeholder would show selected initially (or when the selected value is set to None), but won’t be in the dropdown list (so it won’t be an option the user can select).