Worth to notice the benefit of not submitting all apps within a few seconds of each other, at least with Chase.
When you call recon after a 3BM the first thing you usually hear is "oh, I see you applied today for 3-4 cards, whats the reason you did that?" and of course you can explain all the benefits of each respective card, but...
What I do is, I apply for the first card, decision, most of the time with Chase, is pending. call recon. bla bla bla. approved. apply #2. pending. call recon. asks why 2 cards. bla bla bla. approved. apply #3. pending. recon. asks oh, why 3 cards. umm bla bla bla. approved. apply #4. pending. call recon. asks oh oh oh, why sooo much cards. and now try to explain... only approved after having me conered to awkward positions, luckily she couldnt see my face blushing....
so basically, instead of having the 4th-app-trauma 4 times, I got it minimized to 1-2 times.