I don't know if marketing was involved with using the term 'isolate' or not but if they are isolates as described by companies such as Cloudflare and Google, it might help to speak a bit more about the actual implementation at the infrastructure level. Isolates are a really interesting approach to deal with the inherent nature of scripting languages to deal with the lack of threads as most scripting languages are inh…
V8 isolates are absolutely designed for security. For 10 years V8 was the only security barrier between sites in Chrome. Now they have retrofitted strict site isolation for defense-in-depth, but that doesn't mean the V8 team suddenly doesn't care about security. Chrome wants both layers to be secure and will pay a bug bounty if you break either one.