NFCU would not approve me for a SECURED card until I had proof that my BK was discharged. I cant speak for any other lenders though. They said that if I wanted to add it to the BK that I could later down the road because the TL was opened prior to discharge. What sucks is that I very clearly described to the person taking my app that I was not discharged and asked if I should wait. Well HP and then declined due to not being discharged, and then another HP a month later. Two HP for one secured card, not to mention the HP for opening my checking. Live and learn
You can do the Cap1 Pre-Approval and it will let you know if you are approved without a hard pull. You are almost guaranteed an approval from Credit One and First Premier but they come with hefty fees. I had all 3 before discharge.
I'm not a fan of secured cards and it's easy enough to get an unsecured card after your BK is discharged and the stuff on your CRs is reporting correctly.
There is no solid evidence that a secured card can hurt you, but I stand by my position that they wouldn't put the "Secured" annotation on a credit report if it did nothing. I have a strong feeling (based on mountains of anecdotal evidence) that there are card issuers that won't approve you and/or give you a lower limit if there is a secured card anywhere on your report.
IMO, it basically says "This person couldn't live on cash long enough to let their credit heal to the point where they could get an unsecured card".
All of the above is just my opinion, some people disagree, but I'd go along with the people who are telling you to wait.