There is no doubt that for those doing primarily TLV-LHR (and vice versa) without connections the differences between Silver and Gold are nominal unless you do enough travel to earn the Gold upgrade for 2 etc beacouse in terms of the airport experience there is no difference what so ever between Silver and Gold at T1.

Of course that's only while the flights are indeed going from T1 beacouse as soon as they move out of there even of it were to T3 Golds will once again have more airport benifits than Silver.