At a glance, this component looks very similar to NcInputField with similar interface, states, helper/hint text, public methods, and label. Except a trailing button.

Could it be possible to add a new prop in NcInputField like multiline/textarea instead and use dynamic component?

Maybe making this component a wrapper around NcInputField like NcTextField if we need to assign more custom things.

That was my plan at first but doing so would require a lot of hacks. For example trailing buttons, and leading icons don't make sense here. They look weird as the text extends to multiple lines.

The success and error states are tied to leading icons in NcInputField which would need to be hacked away when using them for NcTextArea.

I went with a custom component to reduce complexity and narrow the scope of NcInputField to make future changes easier.

I agree with @st3iny, the NcInputField is a wrapper around the native input field and this one is a wrapper around the native textarea.
This way we do not need to deal with two different elements, reducing the complexity on the component.