Applying for a credit card in the standard way usually involves submitting a set of documents to the sales agent who collects them on behalf of the credit card company you are dealing with. Although, there isn’t much trouble in this format, there is a chance that confidential information about you such as your salary slips, identification information etc. goes into the hands of people you are not sure are trustworthy.
It might lead to leakage of information, such as phone numbers inviting thousands of marketing calls or in serious scenarios, even identity theft. This is one reason why online credit card application process is much safer and smoother.