The idea with having eBPF in the kernel is that we can limit the amount of trust given to a particular user-space task.
Accepting compiled stuff in the form of a kernel module requires root privileges and requires that the kernel essentially have complete trust in the code being loaded.
Loading eBPF eliminates the need to trust the process/user doing the loading to that level.
The BPF syscalls don't require cap sys admin. Only specific invocations. You can setup a socket filter without sys admin, and a device or XDP filter with net admin.
Sure but how common is that case? How common are multi-tenant Linux systems with untrusted users that give those specific permissions? Do you want untrusted users sniffing the packets of others?
I'm arguing against the in-kernel eBPF infrastructure: bpf system call, the JIT and the VM.
I think it makes more sense to just compile eBPF (or rust or whatever safe language you want) to a kernel module.