Thanks for commenting, it used for different Countries.
C1 is compliant with with UL certification, it can be sold in the USA, and the HM-720 for EU market.
it didn’t has a hard-wired cable in this page, may I ask which model did you refer to?
currently, both of zigbee and matter over thread are provide basic alarm functions, mute and siren functions have not supported yet, if you wish to have more functions like what we did with HS1SA-E now, you may need to wait for a while, but if you just need the basic functions, both of zigbee and matter versions are good choice.