A little background please:
Did you know the phrase conversation piece meant something totally different than what is does today?
According to our favorite site for midnight rabbit holing, Wikipedia, the definition of "conversation pieces" actually referred to a group of people painted while having a conversation:
A conversation piece is an informal group portrait, especially those painted in Britain in the 18th century. They are distinguished by their portrayal of the group apparently engaged in genteel conversation or some activity, very often outdoors. Typically the group will be members of a family, but friends may be included, and some groups are of friends, members of a society or hunt, or some other grouping. Often the paintings are relatively small, about the same size as a half-length portrait but in horizontal or "landscape" format; others are much larger.
Today
The phrase "conversation piece" later acquired a different meaning. It came to refer to objects that were perceived to be interesting enough to spark conversation about them. They provide a stimulus for prop-based conversation openers. Nothing better to save you from that awkward silence than; "cool art piece, huh?"
BONUS
Three obnoxious "art-speak" phrases to say around art:
1. "I feel like this piece is too grounded in futurity to be relevant now, you know?"
2. "This artist is just too cerebral about the post-postmodern aesthetic."
3. "I'm impressed with the transfiguration of the commonplace here."