The business cases for such solutions usually consists of continuous cost around ~400 USD /user/license/year, depending on solution/offer.
The system requires that you upload your data to an server or database.
Difficult to investigate and show the "digital hierarchical trust" during an audit. (your PDF are digitally signed by one external party, but contains pictures of signatures)
Unfortunately, it is not uncommon that you cannot prove "digital hierarchical trust" for your documentation during an audit if you have cancelled your license agreement (one way street).
