Databases are being encrypted encrypted more and more often these days, and there have been some recent cases in which a lack of encryption has caused a major data breach. Most organizations arent using HSMs to perform encryption with secure keys, but they should. Storing the key in plaintext or even obfuscated within the application is akin to leaving the key under the doormat. An HSM is dedicated to processing encryption and securing the encryption process cannot be dumped to gain access to key data.”]
Source: https://securityintelligence.com/how-to-dramatically-improve-your-database-encryption/