I purchased a HomePod and, inarguably, it's an incredibly niche product.
I already owned a Sonos Play:1, which I found to be a really solid product. My only gripe was that, as an older product, the Play:1 is app-controlled. As an Apple Music subscriber and someone who wasn't concerned about the HomePod cost (both niche categories of buyers), the allure of the product was to be able to use voice to control the music.
My biggest problem with HomePod is ironically how you can't app-control it like the Sonos Play:1. The Sonos app had a major benefit: once you loaded your Apple Music subscription, you could use the app on any device connected to your network. This means my wife could browse music in the Sonos app on her phone and play music on the speaker with my Apple Music account. The HomePod, on the other hand, only allows you to browse music from the Apple Music app on my phone and play it to the speaker via AirPlay. So, any other user in my house is stuck using only voice.
Additionally, as many people have noted, Siri on HomePod misses a lot of direction, particularly if there is ambient noise or a conversation in the room. For instance, I may be speaking to my wife, pause, and say, "Hey Siri, stop the music", and get no response from the system. In many cases, it's just easier to walk to the unit and hit the top to turn it off.