We built this product to handle the world's largest datacenters. Now we want to offer that same scale and peace of mind to the rest of the world. Why don't we price based on the amount of data like everyone else? Because that model will eat you alive with unexpected expenses and then we will have to become a billing company instead of a software company. Our data protection and data mover pricing is based on the number of concurrent workers. Each worker performs a "job" and that job performs an action on your network mounts/shares/buckets.
A single worker is capable of migrating/replicating/restoring more than 1B files/objects and 1PB+ of data. You probably don't have a billion files in your network shares. So a single worker can easily handle 1-4 jobs very quickly, but one job at a time. That may be enough concurrency or you might decide to add more workers.
What do we offer? Data independence. Storage technologies come and go. Data is forever.