What are the security benefits from cryptographic hardware accelerator?

I am working with Beagle Bone Black and  want to use the cryptographic hardware accelerator. As per the documentation it just unloads the cryptographic operations from the main CPU and hence increases the performance. In devices like Hardware Security Modules(HSM) they do not reveal the encryption and decryption keys to host system(i,e RAM) and hence prevent from security attacks. Is it happening in sitara processors also? Or is this hardware accelerator meant just for CPU load sharing?