It is highly integrated with other Azure Services
Provides monitoring and logging features
It is PaaS (Platform as a Service) offering

Azure Disk Encryption (ADE) keys and Transparent Data Encryption (TDE) keys are stored in Key Vault
For storing non sensitive application configuration App Configuration (Azure Service) should be used

Secret Management

Key Value pair storage
Configurations for connecting to DB, API Keys, tokens, certificates, etc.

Key Management

RSA or EC encryption keys used for cryptographic operations
Software protected or HSM backed

Certificate Management

X509, SSL/TLS certificates
Supports auto-renewal
DigiCert and GlobalSign CA is supported in Key Vault for managed certificates

Hardware Security Module (HSM)

Secrets and keys can be protected either by software or FIPS 140-2 Level 2 validated HSM Multi-tenant: FIPS 140-2 - Multiple customers isolated virtually
Single tenant: FIPS 140-3 - Each customer dedicated HSM