<p>I can think of plenty of good reasons to using it; however, what are the downsides to it?</p>

<p>(Apart from buying another server)</p>

<p>What are some advantages to using a daily build instead of it?</p>

I don't think there are any downsides to it. But for the sake of the argument, here is
Eric Minick's article on UrbanCode
("It's about tests not builds.")
He criticises the tools that are based on
Martin Fowler's work
saying that they don't let enough time for tests.
"To be truly successful in CI, Fowler asserts that the build should be self-testing and that these tests include both unit and end-to-end testing. At the same time, the build should be very fast - ideally less than ten minutes - because it should run on every commit. If there are a significant number of end-to-end tests, executing them at build time while keeping the whole process under ten minutes is unrealistic.
Add in the demand for a build on every commit, and the requirements start to feel improbable. The options are either slower feedback or the removal of some tests."