When I worked there, I suggested using the prefix feature many times between 2017 and 2024 only to be given a cornucopia of excuses as to why it can't be used.
Code:
https://www.blackhatworld.com/seo/possible-for-bhw-to-add-something-to-market-place-titles-if-they-are-locked.1492886/post-16326294
https://www.blackhatworld.com/seo/what-would-you-like-to-see-on-the-forum.1393473/post-15419954
https://www.blackhatworld.com/seo/adding-a-prefix-when-creating-a-thread.1238377/post-13298498
https://www.blackhatworld.com/seo/proper-punctuation-on-bhw.1147444/post-12397716
https://www.blackhatworld.com/seo/a-separate-method-section.1187094/post-12723531
https://www.blackhatworld.com/seo/successful-journeys-forum.1048966/post-11290602
https://www.blackhatworld.com/seo/a-seperate-section-for-methods-and-guides.1021285/post-10954536
https://www.blackhatworld.com/seo/show-the-forum-name-eg-marketplace-or-hosting-etc-with-a-post-title-on-the-homepage.1000124/post-10715190
https://www.blackhatworld.com/seo/closed-bst-section-in-the-marketplace.977667/post-10638775
https://www.blackhatworld.com/seo/new-sub-forum-making-money-discussions-making-money-guides.948625/post-10145518
https://www.blackhatworld.com/seo/suggestion-require-sales-thread-titles-to-be-relevant.934649/post-9981365
https://www.blackhatworld.com/seo/a-few-suggestions.1078861/post-11640414
However, they allowed it when another manager asked for it for the FRC section in 2023, so this recent update doesn't come as a surprise. Given that they used it for a section that's indexed, I see the old "indexing" excuse I was given conveniently no longer applies.