Granite and Dekton are the only materials commonly used outdoors in continental Croatia; indoors there are no restrictions.
For outdoor benches there are options for lower and upper drip edges. Also ensure a minimum overhang of 3 cm after finishing.
When choosing stone for stairs, decide how to achieve slip resistance on treads. Finishes can be flame-treated, brushed, sandblasted, shot-blasted, but not polished. If you choose polished finish, consider whether parts of the treads will be cut, sandblasted, shot-blasted or have anti-slip strips added.
In interior spaces there are generally no restrictions on material types and finishes. You are free to choose what you like.