If you delete it, and you lock up your phone installing something from Cydia or other, and do a respring/start, SHSH will open automatically and you can SHSH in and fix things. You'll need SBSettings to do so (which will also allow you to go to Power>Safemode and turn things off in Winterboard). Nice to have the option to go in there at will. You can change your password using MobileTerminal (not the one on Cydia, Google for the most recent or go to XSellize for it).