The principal value proposition of L37-3L is that it exhibits all the desirable characteristics of a non-silicone gap filler combined with the softness of a silicone based product.  This means that key engineering decisions can be made without resorting to harder materials.  A softer material such as L37-3L will also allow larger tolerances to be dealt with and this can reduce the machine costs for cases, heatsinks, and chassis.