it's kinda useless to download every update, it's just that every changement is uploaded so we can see what is done when it's done instead of having to wait for everything to be done befor knowing that it's not dead
also, less pressur from the deadline as if you update less frequantly you get asked for update prety often, with this short time between update even if not much is done, ther is no asking for update every days
and this way ther is no rush for finishing a featur befor update.
and to finish, if a bug is found in an update, as ther is not much changed, it's easyer to find and fix as ther isn't a bilion more new line of code to check