I dont quite follow your question, with visible you need to have a mobile device connection as primary. In addition to that you could add Apple Watch with $5/month with GSM LTE connection. (Note there are two versions of Apple Watch one with GPS only option and another with GSM+GPS option).
The $5/month plan is for GSM+GPS option watch. Where we can use the watch to call, text without the iPhone nearby. For the GPS only watches you can call, text but you should have the iPhone nearby because those calls, texts piggyback on your iPhone service.
So to my knowledge, visible doesnt have option to support Apple watches as primary, so you need to have an account with visible for mobile plan and watch is additional.
Hope it answers your question.
P.S: Please mark this as solution if it helped you.