I completely understand the purpose of this update, however I can think of two scam situations, and I'm wondering how sellers will be protected.
I understand that Fiverr Buyers who are also Fiverr Sellers won't be able to leave reviews in this case, which is good. And first-time buyers also cannot participate. But what if there is an established Fiverr Buyer who is also an Upwork Seller? I think you can see where that would lead.
If it is found that there is a scam account on Fiverr (who is hired on another platform to leave fake positive or negative reviews), how soon will they be found and disabled, and what will happen to the fake reviews that were left and had harmed a Seller's account (or boosted some other account with positive reviews)? Will they be hidden/removed?
As sellers, we can partly protect ourselves from scams by simply not accepting cancellations. That would put an end to most of them.
However, aren't there ways that Buyers can force cancellations without the Seller accepting the request? Please correct me if I'm wrong. It seems it has happened a few times. If staff can reassure us that Buyers cannot simply force cancellations after delivery, than that will protect us in the long run.