No it isn't a dumb reason. They are not adding the SDD-1 compression until the final Star Ocean patch is finished to prevent n00bs flooding the ZSNES board with requests or problems. It will be in ZSNES very soon, and you have gfx packs anyway until then.
And using the registry is a backwards step. Visualboy Advance just got rid of the registry which is a good thing because it is easily alterable. A reg key is bad for many reasons, such as n00bs not knowing where the reg key is, as well as it being practically ineditable. A CFG/INI file can simply be deleted to "reset" the emulator much more safely than fiddling with registry settings.