In this case, with the SP builds, that is still a poor implementation.
First, just because Apple does something a certain way doesn't mean that it is right for every company to do things in that way. With OS updates, one might prefer to let several days/weeks/months go by before checking, depending on how out of the loop/paranoid one might be.
With a small company making multiple builds of a program each day, such an update practice is out of schedule with the number of builds. Now with the regular builds, update checking at one's leisure is fine.
Also, another small company like Flip4Mac, which I believes checks for updates everytime you launch the QuickTime Player, and that seems to work fine.
And also if you consider what one's connection type might be, checking for OS updates might be better on a monthly scale if one is on dial up, versus nearly unlimited bandwidth on broadband, where hourly might be fine.
I would presume that anyone interested in downloading 18 MB files several times-a-day is not on dial up, so for the SPs there doesn't seem to be a reason to limit it to every 24 hours, instead of when the app is launched.
SC