On a large $ value item why do I have to give credit card info to CONFIRM BID?

[fun39nel]

Motorhome bid/purchase

[heidilynn0_3]

Hi fun39nel .. $15,000. is max without a card added..

http://pages.ebay.ca/help/buy/bidding-overview.html

[femmefan1946]

The seller does not see your credit card information. This is used by eBay as a quick and dirty method of confirming identity and credit worthiness.