It’s also a bit of an odd question along with those other HR orientated questions that have little relevance for the job at hand. It’s the interviewer’s job to decide what makes you special based on your CV and interview responses. Answering that question puts a skew on things.
How are you supposed to know what makes you more special than the 20 other potential candidates applying for the same job? The questions being asked should be relevant to the job so they can determine what’s special about you for the job compared to the other candidates.
Rather than ask what's so special about you they should ask why they should pick you. You might answer that you're punctual, flexible with hours etc and will have evidence to back this up. None of those answers make you special, they make you work focused - If that makes sense
At least that’s my experience having had many interviews as a short term contractor for 2 years in the past handling various IT projects.