How would it make it easier to check for updates? Right now if the date changes on the file on the server, you KNOW there is a new, working bootloader. If it were updated daily, you'd have no way to know if it works, or if it's even changed, until after you install it and test.
The bootloader rarely changes, but changes to other code can affect how the bootloader works, breaking it, and until someone goes back and fixes it, it's entirely unsuitable for use. DAILY BOOTLOADERS WILL CAUSE MORE BUGS. They need to be tested before they're released to at least verify that they boot up, load Rockbox, and leave your player in a state that it can be recovered if the Rockbox file is bad.