It seems that with ebpf you can read data before TLS encryption : Debugging with eBPF Part 3: Tracing SSL/TLS connections https://blog.px.dev/ebpf-openssl-tracing/
Routing real app traffic through an intercepting proxy can be a real time-saver depending on what the researcher is trying to do. E.g. if they want to automatically tamper with a parameter in a request that doesn't happen until after some kind of authentication/session setup, it's much faster to let the app do all of that and configure the proxy to just make the one change, versus having to write a whole client that does all of the initial steps and then makes the modified request, or writing an eBPF filter that makes the changes the researcher is interested in.