Don't feel bad about a store card being your highest CL. I was in that situation twice when I decided to actually put some effort into building my credit. GE's JCP was my highest CL when they gave me 1800 CL after a CLI and later when I applied for a Target card they gave me a 3000 CL. The Target card I got when my CU Visa had only a 2000 CL. It does help your util and it will help your AAoA as the account ages, so it is all good 
Look at the positive and do not fret over it being just a store card.
As for the BBRZMC, I had one and dumped it a few years ago. I got tired of the $59 AF and lack of CLIs. I had that card for 2 or 3 years and went from 300 to 850. My Sears MC from HSBC was even worse, I sat at 300 CL for years and still got nailed for another $59 AF.
One thing you do need to remember, HSBC is the underwriter and the deal that is made between the retailer and underwriter varies according to the needs of the organizations in question. Once you throw the MC, Visa or Discover name into the mix as well, now you have three sets of criteria that must be met.
Congrats on the new store card and do not go too crazy on it, love cannot only make you blind, but screw with your fico 
