Ask HN: Is SalesForce overcharging for database space?

We just migrated from Freshdesk to SalesForce for our CRM and what take up 1GB in uncompressed CSV-files is eating about 5GB of table space in SalesForce.

Never seen this blowup GB in any other CRM database. This is for standard Case, Customer, Contract, Email (attachments not included).

Extending with 10GB have a very high cost compared to any other system I have seen, even after heavy discount.

I get this feeling that SalesForce is overcharging by calculating a higher database size, than what is actually used (including temp space?). Or is it any other explanations?