PET Vs. CLT

sir why would a person want to go for a CLT instead of a PET? In case of PET at least there is some scope of no IHT being payable at all(case where the donee lives beyond 7 years of transfer). But in CLT it is obvious that upon transfer IHT would be payable immediately and later too(if the individual lives for less than 7 years after transfer, similar to PET).

thanks in advance