Whats the point of sd card if it doesnt record?

I use 2k indoor pan&tilt.
My apt doesnt have camera and i decided to hook this cam to AC battery and place in my car to record overnight. (Some asshat already hit my car twice while parked, idk who did) Of course there is no internet around parking lot but what i thought was that, it will record every motion detection and save it in SD card, then viewable once connected to internet through app. Today I brought my cam in and connected internet to check, no event recorded! What a shame! Then, whats the purpose SD card for?