One must be very careful when shopping online especially when you think your shopping in a secure environment.. The golden lock means absolutely nothing if they automatically send all users information to say a yahoo mailing account then copy and paste the client credit card number and other personal information to a third party credit card processing software. The information is still saved in a yahoo email account and though the owners of such websites claim to delete all account numbers they do keep some with information that should not be available even to the admin of the website. I know of an Acupuncture supply company in New Hyde Park, NY that sells online and has this very exact system. When the owners told me to take part in producing a website to act in this manner much like thier already existing one I refused due to my ethical belief in building truly secure websites that protect the clients personal information and are PCI compliant.
It is important that developers, development companies or consultants like myself only represent the highest level security even if it can lose them money.
The only reason a company would need the information is for two main reasons helping in stealing peoples identities directly or indirectly or cheating a merchant service company out of fees that would normally be paid if they were properly registered as a online company.