One aspect is that we have a lot of data that has PII in it, and we feel safer if we anonymise that locally before sending it into the cloud. Once the data is cleaned up it's actually sent to GCS for consumption in our product). Another aspect is that this data has to be accessible as windows fileshares (i.e. SMB) to our data processing team. The datasets are in the range of several 100's of GB to several TB, each of the team members works on several of those datasets per day. This would strain our uplink too and maybe the bandwidth would be costly as well.