Will you asked to give another solution to a problem that is no more optimized than your current one?
ie, a tree-related problem has 3 ways to solve, time complexity is same across. Space complexity is such that recursive dfs is worst due to stackoverflow risk, followed by iterative DFS and then iterative BFS.
1) iterative DFS
2) iterative BFS
3) recursive dfs
Now, if you already gave a working iterative DFS solution, how likely is the interviewer to ask you to 'solve it another way', even though any other way is not any more efficient?
I can see if you give a recursive dfs solution, you may be asked 'can you do it iteratively to eliminate stack overflow risk', but vice versa?