I broke my parents' smartphone as they laid in bed
What would you do if your parents broke your phone?
I'd ask them to wash my fucking dishes.
Intentionally breaking or damaging an expensive item that belongs to someone else like a smartphone is very wrong and especially so when it is done as retaliation against your family. Family members are supposed to support one another and not damage others' property. You should apologize to your parents for your actions and purchase them a new smartphone to replace the one that you broke.
No, it's not necessary.
Why do you think that it is unnecessary? You should not break things that are not yours, but if you do, you should replace them at the very least.