You must have a smrtPhone subscription to be able to get and use smrtDialer.
However, smrtDialer seats are not named, which means that any user can be moved in and out of a smrtDialer seat by Users on your team with applicable Activity Management permissions.
Also, your smrtPhone and smrtDialer users don't need to be members of your CRM workspace to use any of these products. There are some differences between smrtPhone users who were invited via CRM and those who were invited via email and you can learn more here: Invite users in smrtPhone ⇢
