One big one is that people are more likely to have that VM installed already. The thing with languages that compile to bytecodes is the user has to install the VM/runtime; if you piggyback off Java with it'sits [googles] 5.5 billion devices, not only do you save the work of having to implement and optimize your own VM, you save the work of having to host and package it, and your users save the work of having to install it (or the disk space/time of having it installed automatically).