Why does the plan set volume and not modules?
Because the cost of running the infrastructure follows volume, not the number of features switched on. Charging per module would make you choose between having a CRM and having business mailboxes; charging by volume keeps them all in the same account.
Is the volume a single balance for every channel?
No. Each channel has its own monthly quota — what goes out by SMS doesn't consume email marketing, and vice versa. The comparison above shows each channel's volume in each plan.
What happens when I go past the band?
When a channel reaches its monthly quota, that channel's sends stop until the month rolls over or until you upgrade — the refusal is explicit, not a silent disappearance. The other channels keep sending.
Do I need a card to start?
Not to create the account. You subscribe inside the platform and, for now, each order goes through team approval before the plan is enabled — that's when we talk about domain, list and sending pace, to prevent the problem instead of fixing it later.