To deter fraud. An impartial witness (a Notary Public) ensures that signatories to documents are who they say they are and not impostors.
A Notary Public ensures that signatories to documents have entered into agreements knowingly and willingly.
In a society in which national and international business dealings between strangers and nationalities of different countries are the norm rather than the exception, a Notary Public creates a trustworthy environment where strangers and foreign nationals are able to share documents with full confidence in their authenticity.
Notarised documents also are considered self-authenticating, which means the signatories do not need to testify in Court to verify the authenticity of their signatures. Having a document notarised is “a huge strategic advantage” in litigation.