We do not do process isolation yet, although we have plans to implement that as well as a fallback strategy.

The advantage of the native-image-isolate-based isolation is that it is much more lightweight. For example, calls from and to the host application are much faster. There is no copying or expensive synchronization necessary. The disadvantage is that we need to do our own protections against attacks, as the OS protections between processes don't apply to such isolates. By default, we deploy software/compiler-based protections but are also very close to supporting hardware like Intel MPK.

If you have more questions, you can also drop by on Slack; we are a friendly bunch: https://www.graalvm.org/slack-invitation/