I would rather be able to speak one other language perfectly. Weighing the benefits, being able to speak every language enough to get by seems perfect for travelers, but I’m not the sort of guy who wants to go traveling all over to all manner of countries. If I can speak one other language perfectly, that opens up a ton of options. New people to talk to. New media to consume. And it would look great on a resume.
Would you rather bring back someone from the dead to live another full life, or erase one person so they never existed in the first place?