Split Categories, CC Payments and budget

Hi
I couldn't grasp that split transaction stuff and it's benefits, so id like to learn about it. and would like to ask why credit cards dont have a particular kind of account where we could make an easier kind of bill payment. lets say it could be like this: when we create a CC account we could choose another account where the payment of the CC would debit its found do credit on the CC.
Other problem that i see is that i bought this month in 2 installments a tablet with mu credit card and put the purchase date on the transaction under my cc account. the first installment will only be part of my expenditures on the next month but in the budget area of financisto i see that the program is counting it for THIS month. so i would suggest that the budget would take the date of the bill payment into account.