What is the ruling on collecting artifacts and antiques, and is zakat obligatory on them if they are collected as a hobby?

We have previously clarified the ruling on acquiring artifacts in Fatwa no. 51394. If the aforementioned antiques are acquired for decoration or as an investment, they fall under the ruling of artifacts. Otherwise, please clarify their intended purpose. Zakat is not obligatory on them unless they are made of gold or silver, or intended for trade.