According to firmware update leaked by Apple, the HomePod is expected to run a version of iOS, just like your iPhone. But unlike your iPhone, it seems Apple’s smart-speaker is not going to support third-party apps at launch. This means you won’t be able to ask the HomePod’s always-listening Siri to request a Lyft, buy movie tickets on Fandango, or order Domino’s pizza.
Initially, I agreed that the HomePod should run third-party apps on day one but I’ve walked that back somewhat recently. I think that the fact you can AirPlay things from your phone will work well for 90% of people until a proper, carefully considered solution (ie: a HomePod specific App Store) is put in place for devs and customers to take full advantage of.
You have to keep in mind that the original iPhone launched without an app store and the Apple Watch likely should have done the same. I think allowing people to get their hands on the device and really interact the core features is important before you start piling on features that people may or may not actually use. For example, ordering a pizza with a Google Home sounds neat but is actually somewhat of a mess in execution.
I would have to imagine that by WWDC next year, we’ll be hearing about a new SDK that third-party developers can use to start creating new experiences for it. I think this approach, in the long run, will be better for both devs and customers.