I'll probably add Sims3Pack support, but SimRipper can't read store stuff if it's encrypted. You could decrapify it but that can cause problems. SimRipper is probably never going to support store items.
Using decrapify on store content does break them, but only if you use the actual decrapify.exe. This is because decrapify renumbers the internal resources of Sims3Packs, which means they'll effectively be considered separate items.
If you use s3rc.exe instead, it removes the encryption but keeps the links and references intact. So you should be able to do it that way for any content you own.