From the way this post is written, it sounds like you are confused about actual online banking and credit usage.  As some of the others mention, online banking gives you the convenience of tracking deposits/withdrawals, transfers, and online billing.  You can use this in conjunction with a debit card which is similar to a bank card for immediate payments instead of carrying cash.  This is not something you use then discontinue, it is a service your bank provides free of charge.  Credit cards, on the other hand, are services which provide the convenience of tracking credit charges and ease of payment online, eliminating the need to post hardcopy checks by a designated date.  The service is also free.  As to how secure they really are, Laurie makes a very valid point. 

If you are very concerned about secure online transactions, then purchasing a rechargeable cc could be the answer for better tracking.  Even designating 1 particular cc for such purchases, is much more manageable than balancing several cards at once.  But if you pursue this option, I would recommend never canceling those credit cards.  Doing so will dramatically affect your credit rating, and raise red flags concerning how you manage your finances in the long term.