The understanding current state is crucial to understand.
The current state of an initiative is the starting point. Without a starting point, a map is meaningless.
Without a current state, you will never know if everything that should be in the future state is in the future state.
Without a current state, how do you understand what the future state needs to support?
Without a current state, you will never know if there are things missing in the future state until a stakeholder goes to use them.
A business analyst, as a change agent, leads the business from where they are (current state) across the gap to where they want to go (future state). In order for the map across the gap to be complete, the current state needs to be well understood.