After the announcement on Friday, Steam did issue an apology, “We know it’s a bit of a hassle and we don’t like making trading harder for users, but we do expect it to significantly help customers who are tricked into downloading and running malware from losing their items.”
It is said that third-party trading services approved by Steam have received an exemption from the CAPTCHA obligation in order for them to function as normal. I would say that this is a necessary evil then, just like how air travel has changed ever since 9/11, where liquids more than 100ml are no longer allowed on board, not to mention the far more stringent security measures taken at airports, such as removal of belts, shoes and notebooks, among others.