Having seen... things... unless it's written by people with the right skillset (and with funding and the right environment), that it exists doesn't mean you should use it (and the phrase "it's a trap" comes to mind sadly). https://scicomp.stackexchange.com/a/10923/1437 applies (and note I still wouldn't call Julia mainstream yet), so while I'm not saying people shouldn't try, the phrase "don't roll your own crypto" applies just as much to the numeric and scientific computing fields.