Having all your eggs in one basket is deemed to be a risky solution by many.
When I first started out in photography, I was taught that having multiple smaller memory cards was the way to go because if one card fails, you'll still have a few images to keep on other cards. This was what I thought was true until I bought my Nikon D800E. The problem is the ridiculous 36mp image of the Nikon D800E which in turn forces you to purchases larger cards. An 8gb card will only give you a mere 200 images and when shooting weddings (yes I still shoot weddings, but for Jason Tey Photography), it is not ideal, so I reached out to B&H and got myself 4 x 64gb cards.
Since then I have not looked back and I'm planning to purchase more!
Why? You may ask. It is because I lose my cards all the time. The more I have, the more I lose, plus the more I lose track of what is in what card. Misplacing or losing a card is just like having a card failure and by having a large memory card means that I won't have to switch cards during a job. Especially for weddings, where many "moments" have been missed due to the "card full" issue.
Pros and Cons of having large memory cards
To me, the pros weigh out the cons and besides, nowadays, most professional cameras come with two slots, so you can always set one for mirroring backup.