heh , ok..here is an example why i use a user-startup.
i install a dodgy patch/hack from aminet or anywhere else , it crash on boot.
IF i had removed my user-startup and it would have been in Startup-sequence , then i wouldnt know whats going on, because my gfx card drivers starts in the end of the startup process (startup-sequence) , so i would have to rig up a tv or whatever to see what went wrong , instead i just use user-startup

anyway if anything crash in userstartup then you could normally just break it and loadwb/endcli.
..
anyway i know why you wonder if its useless/should be removed because for new users or not so experienced ones will think of it as " A MESS" , anyway i really dont see how u an win boot time on removing user-startup , my userstartup is only a few lines , its not a big messy file, and its sorted well out and i would recomend everyone to do so, clean it up! , remove all reduant #### in it.
cheers