No adoptable storage. What does that mean?

Owning solely nexus phones, I haven't had an sd card since the nexus one, so this means absolutely nothing to me, but reports state the s7 isn't using googles adoptable storage function.

Would I still be able to apps on the sd card? Or only on internal storage?
Can I save Titaniumbackups and twrp/cwm backups on my sd card?

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