The 30 minutes isn't to for "collection", it's for announcement checking. If there's a hard fork and people are potentially going to lose money, we need users to be aware as soon as possible.
You don't need to send the installation ID when checking for announcements. Why would you need that?
So that we don't "count" that ping as a unique user. Our goal is to get a rough gauge of how many people are using Armory, and what the OS & version distribution is. That's all we use the data for. If we send a ping without the ID, we don't know if it's a duplicate.
Also, I shouldn't have suggested "just" hard-forks... a piece of secure software used by people with massive amounts of money has many different reasons users might need to be notified, including critical security issues with Armory, if they arise.