You can choose to have your account deactivated" because that's what i did 3 years ago. The thing is though that you're right that the information is out there for good because you can always reactivate your account and pick up were you left off.
It was common and is common knowledge that social media websites and apps were and are mining your data to sell to 3rd parties. Combine the fact that studies are now showing people that social media makes you more prone to being lonely and depressed its no wonder that social media is actually more harmful to you.
3 years ago people were like, "Johnnny your weird and strange for deleting Facebook", now i hear "I should just get rid of Facebook like Johnny did, etc.."
Heheh, im awesome!
Don't worry though. You got a smart phone? No problem, all the data facebook would have gotten from you gets mined from off those things too.