Security implications of using Primary Key

First of all: thank you for the great plugin. Works flawlessly.
Regarding topic: It feels like bad practice to use Primary Key. From security standpoint if for any reason the key compromised – the cloud storage account can be abused in variety of ways. For instance someone can upload 200Tb of p%rn, and owner of the account will be billed for it. Moreover it exposes different storage services! Policies may help somewhat to mitigate the issue.

The good practice in this case is to use Shared Access Signature. Besides it does not expose the whole service to potential abuser it is also provides possibilities for variety of limitations: starting from limiting list of used storage service types and going to source ip filtering.