1) Twitter certainly has the right engineers to do this. 2) If they can speed up Scala compile times by 5 minutes a day (extremely conservative -- compilation

1) Twitter certainly has the right engineers to do this. 2) If they can speed up Scala compile times by 5 minutes a day (extremely conservative -- compilation times tend towards 1s per file), across even 1,000 developers (Twitter had around 2000 when I was there) that immediately funds a 5+ person development team. This isn't the sort of thing you throw a huge team at, anyway. 3) It helps with recruiting talent who is looking to work in environments that have strong type safety, or who just want to work for companies willing to invest time in making their software engineers more productive.