So is it worth it? for $199?
I've got one, went sonos shortly after
I keep the HomePod because I use home kit, and it's convenient.
if they ever add siri to sonos (since Alexa and goole are already there) or they come out with something comparable to the echo dot, I'll sell the HomePod.
if you don't have Apple Music, siri on the HomePod isn't happy, All she wants to do is play music.
a couple times a week, I'll ask siri to do something with lights, and she'll say "there's nothing playing on this HomePod"
once or twice a month I'll ask her to turn on a light, and she starts playing random music (not from Apple Music obviously, but some tune in stations)
and sometimes she cuts off the end of my sentences, meaning she acts on a partial command, and normally affects the entire house's lighting.
look at sonos, all of the apps you mentioned play directly on the speaker, so no need to fiddle with airplay
and they're a bit cheaper than HomePod, if you find the right sale, you can almost do 2 sonos for one HomePod.
Since the music plays on the speaker itself, you can use any sonos app to control it. (start music from your computer, and change the volume or skip a track from your phone)
with sonos, airplay actually works (I've seen several posts here, about airplay to a stereo pair from a Mac not working on HomePod)
and in the grand scheme of "smart assistants" siri is in third place of three
great for homekit, but "general knowledge" questions are hit or miss,