The Korean expression A/V + 을 뿐이다 is used to emphasize the limited scope or simplicity of an action or state.
In English, it's often translated as "just" to denote that nothing more than the specified action or state is taking place.
The A/V + 을 뿐이다 structure is useful for situations where you want to emphasize that you're doing something and nothing more.
It helps to clarify your actions or state, especially when there might be misunderstandings.