It works. It’s uh… ‘simple’ but it works. Both Alexa and google assistant.
Personally I have Alexa. But by all accounts it’s similar with Google Assistant : https://www.theverge.com/2018/9/19/17806186/simplisafe-home-security-system-google-assistant-voice-integration
You can tell it to arm, or ask it ‘are you armed’.
You can NOT tell it to disarm.
And it requires the $25 monitoring plan. The basic $15 plan doesn’t do automated ( or indeed app ) anything.