It's fairly new. It was announced at JuliaCon last month (early this month? I forget) that it will soon be the default recommended way to install Julia moving forward. I'm personally hugely excited about it (Julia's been my main squeeze since v0.3-alpha). They just need to work on non-interactive installs so it's easy to incorporate juliaup in a docker container (this may actually be fixed, haven't checked in a couple weeks).