That is to evade interference with the network link. AFAIK, the radio tech used is not designed to withstand modern denied environments, which makes it more vul

That is to evade interference with the network link. AFAIK, the radio tech used is not designed to withstand modern denied environments, which makes it more vulnerable. The fiber optics are a cheap way of addressing that tactically and it is proven tech — a lot of older anti-tank guided missiles are controlled the same way. Sophisticated electronic warfare systems are designed to affect much more than the communications link; they have to be effective against systems where the RF link tech is designed to survive heavy EW environments (such as what the US uses). EW and countermeasures are designed to attack the onboard systems themselves, since they are intended to be effective against fully autonomous systems that are not being controlled over a network link.