As a matter of fact WebVM and BrowserPod share the same kernel, the difference is all on the performance side.

WebVM uses x86 virtualization and hence has a significant performance penalty, with the upside of running any existing software without needing the source code.

BrowserPod on the other hand runs WebAssembly binaries at almost native speed. Source code is required, but that is a fair compromise in the world of sandboxing. Most language runtimes and CLI tools are FOSS anyway, and many closed-source tools (such as Claude Code) are written in scripting languages and run on top of FOSS engines.