Let us not forget Zaino established its repetition for durability long before ZFX was invented. :xyxthumbs
Though I am a ZFX user most of the time, the final visual cues of applying Z sealants without or without ZFX is IMHO are the same. I have beta tested many of Sal tweaks and one of the trials is the usage of ZFX and Z1 for initial application. The "visual" difference between the 2 processes after 24 hours is nil. These test are done in a contolled environment (garage)
Where ZFX shines is for the detailer who faces the real world and can not allow his/her vehicle to be idled 24hrs in a garage. A ZFX'd applied coat is immediately ready to face the world at full or final brillance and protection capacity. Let it rain, fog, dew etc. No problem. The cross-linking and bond formations are completed. You can even top with Z8 for enhanced beauty immediately after with no ill-effects on the newly applied ZFX fortified coat.
There are advantages to using ZFX but not to the point where it is an absolute requirement to obtain that great Zaino appearance, real wetness and depth (both mostly prep derived) that last for beyond that first wash or drive though the rain or snow.