Okay so based on what I have read from everyone's response...I can see that a majority of those who said "no" are either hobbyist or aren't doing photography professionally where they see a must for dual card slots. (those doing professional landscape, studio..I can see why you don't find yourself needing dual card slots)
I also noticed that a majority of users here care mostly about size (in my opinion, the Sony a99 is already quite a normal size camera and the a7Rii is really small. Again, in my opinion)
Those who said "yes" are most likely working professionally (like myself) where a small mistake of losing photos for your client, and you can be sued. This is where I see a7 users want dual card slots. (especially large weddings where clients are putting a large investment into your work) This is because it can happen and nothing is perfect. Though it never happened to some people, it's waiting to happen anytime.
Recap: I can see that a majority of the users here are hobbyist (yes there are some professionals, don't worry I didn't miss you)
Don't get me wrong though! I respect everyone's opinion on their thoughts about dual card slots! I just realized that the target audience about dual card slots specifically is entirely different here than other systems.
Happy shooting, everyone!!