HTTPS vs HTTP inter-service connections

[mculibk]

Hi there!
This is probably a dumb question… but I would really like to clarify things (at least for me if I’m getting it wrong).

So… are the inter-service communications between various services (kopano-core, kopano-webapp, kopano-dagent, kopano-archive…) really required to use HTTPS or should the plain HTTP be “functionally” the same?

In the documentation it’s mentioned the SSL certificates are used “to authenticate clients” (services connecting to kopano-core).

I can understand that SSL would protect the traffic and ensure the “right” machine/service is accessing kopano-core… but, is there any other “authentication” done by using https/ssl? (no usernames, nothing similar)

If we don’t count the encryption and “client identification”… is there any other benefit (or requirement) to use https connections instead of plain http?

Thanks!
Regards,
MCulibrk