It's usable if you don't need documentation or libraries. If you like hanging out with drunks on IRC to get bug fixes. If packaging isn't important to you. If you want to deploy code from Git checkouts every day. If you don't mind that Rakudo has been trying to get rid of Parrot for several years. If it's okay that the spec isn't even finished for things like lists or containers. If you're okay being like the third or fourth person using it for anything real.