If the EPS (expanded polystyrene) is covered by fiberglass insulation and/or drywall, it will last sufficiently long for you to escape from a fire.
Just looking up the product now, the brochure says "Please consult a fire engineer when specifying GreenStuf insulation ". That certainly didn't happen. Oops. But as another replyer said, it doesn't really matter for a normal house. It might burn down but you'd have escaped because of smoke alarms and just walking out the door.
The polystyrene is exposed to the outside with no covering.
You probably don't live in the same country as me so the rules are different.
No. EPS offgasses badly when heated. It also assumes that your coverage is 100% in drywall.
If you have fibreglass, then you are sunk. Rockwool/mineralwool then you are much better.