My job uses G-Suite as well and even then we use SMS mostly and occasionally Slack for projects that include multiple departments coordinating. But like you said, pretty much everyone is either using Android Messages or iMessage as their go-to.
We have the Google suite for email, calendars and stuff for work. We use Hangouts as a group chat. I also use it to chat with friends rather than FB messenger.
Edit - For texting though, I don't actually know anyone that uses Hangouts. Everyone I know uses Android Messages or iMessage.
Yep - I know literally no one (personally) that actually uses Hangouts - maybe a scant few who tried it back when Google+ first came out, but that was it. Outside of regular direct texting or FBM for those you connect with there, WhatsApp seems to be the go-to 3rd party messaging for everyone else.