Parking mode is more for when people come back to a car that has been parked and notice damage. So you generally know something has happened, and so easy to just pop out the sd card to transfer files.
If you want to review a constant live feed, even a cheap IP camera would be higher quality than the 640x300 or so preview resolution. If the car is parked for a while and you want to see if anything has happeened just based on video review, as you would have to transfer each video over wifi, which would be slow. with an IP cam and DVR, you can quicly slide along the recorded timeline quickly from whichever recording device, phone or DVR.
A possible general consumer reason for auto wifi in parking is for people who are just popping in to shops when parked, taking a bit longer than planned and just want to quickly check on car, but as the wifi range is so short, there wouldnt be a lot of point.