The way I would put it as someone who works at Beeper is: only use messaging automations for personal use, and don't use it to spam anyone or do anything you wouldn't do yourself within the app.
As long as you don't abuse and keep your usage within the parameters of any human, you'll be fine.
...until Meta decides they want to offer this kind of thing themselves and ban everyone else. Building your SaaS on top of someone else's SaaS is always a gamble, especially if said product is directly sold to users already and not a pure b2b intermediate.