I don't have an ebay account but if I did I would put a credit alert on my name at the credit bureaus. Its free and does not impact you in anyway unless you are in the process of buying a car or house or some other big ticket item requiring new credit. A single request puts the alert on all the major credit bureaus.
Its not just about hacking your current CC but identity theft and opening new credit in your name and charging thousands of dollars before they are shutdown. The aftermath for the victim is years of effort getting it all straightened out -- including the nightmare of credit agencies not believing the client that they got hacked. Not to mention indifferent police departments that hide behind jurisdiction issues when the crime spans multiple counties, if not states.
With the leaked ebay info all they probably need is a SSN to open store credits and I am sure the crooks have other databases to cross with this info to get a complete set necessary to open an account. And don't forget about phishing calls, now that they know so many details about the users the crooks can call them and credibly pretend to be various institutions that the ebay users have a relationship with and thus coax more info out of them. The elderly are particularly prone to this type of scam.
I have a friend who's identity was stolen and it was a nightmare. The crooks opened numerous store accounts in his name, typically for furniture and electronic stores. They had the goods shipped to some address and then sold it, ironically enough, on ebay. All told they got away with over $80,000 in theft. In cleaning up this mess my friend discovered from the FBI investigator assigned to his case that he was lucky -- all the theft was in another state and so there was no disputing that it was him and the crooks exceed some magic number of dollars and thus it was an FBI issue not a local police issue. It still took him over a year of work to get it all resolved.
I recently got some obvious phishing calls which is why I put a fraud alert on my accounts, it cost me nothing and has no impact on my ability to use my credit.
https://www.experian.com/freeze/center.html