No, fw6.0 isn't required for the new search as mentioned in the post directly above yours.
Not sure why people find Sony's firmware numbering so confusing this gen. They increment the version number annually. We are going to version 6 because we will soon enter the sixth year of PS4.
Anyway, no consumer-facing features is not the same as no features. One of the best PS3 updates appeared to have no features but we later discovered that a chunk of RAM had been freed up for use in games, and was a major reason why late gen games looked so good compared to earlier ones. Could be the same here, but we won't see the benefit until games are released that have been compiled against the v6.0 SDK.