Still don't buy it.
The OP had a close lightning
strike. Without the little green light, and even with it the performance of the galvanic isolator, could be unknown or compromised.
The whole point of insurance is to put you back in the position you were in before the accident
That means that you don't upgrade your equipment
but replace in kind.
You are also allowed to effect the repairs
in an expeditous manner, and are you required to perform the repairs
The cost of testing, or the risk of having a device not work is not your problem.
Change the damn thing.
The two points that make sense are the deductable, and the green light, (although I wouldn't neccesarrily trust that.