Yeah, the full duration fallow period QT (usually recommended as 76 days) to prevent disease is a good way of preventing ich/velvet transmission via corals, inverts, macroalgae, etc. though the odds of these spreading the disease are relatively low in the first place. Personally, out of an abundance of caution, I would recommend quarantining in batches rather than not (unlike recommended in the article above) to ensure that you don't somehow transfer the free-living stage of the parasite into your DT, but that's just me.
This is not only good disease prevention practice, but it can also help you prevent the introduction of things like aiptasia, vermetid snails, and bubble algae into your DT after you add a new coral frag or something (you just keep an eye on the frag/invert/whatever during the 76 days to see if these or similar "pests" pop up while in QT - they'll be a lot easier to see and remove in a QT in many cases than they would be in the DT).
