I thought so too, but apparently on starlink roam you can pause service (by the sounds of it, indefinitely), only restarting when you need it:

> You have the ability to pause and unpause service at any time, with billing occurring monthly.

Source: https://www.starlink.com/support/article/dd5b43b5-20e1-b29b-...

If you're not using it you don't have to pay the monthly cost. So buy the dish and just don't activate the service.