I have the same question, which assumes a 'Simple Deployment' deployment (https://helpcenter.veeam.com/backup/vsphere/simple.html
In this scenario, per the document, 'The drawback of a simple deployment scenario is that all data is handled and stored on the backup server locally' ... but another drawback is that archiving is not possible, without using a backup copy job and duplicating the amount of data on local disk:
1. Allocate local storage for a backup
2. Allocate more local storage for a backup copy job, allowing the archiving options
My takeaway is that archiving doesn't fall under the 'Simple Deployment' scenario. Presumably this is to enforce the 3-2-1 model?